diff --git a/blockchain/v0/reactor.go b/blockchain/v0/reactor.go
index 9c4634f2c..d9e0a2e83 100644
--- a/blockchain/v0/reactor.go
+++ b/blockchain/v0/reactor.go
@@ -63,7 +63,7 @@ type BlockchainReactor struct {
 
 // NewBlockchainReactor returns new reactor instance.
 func NewBlockchainReactor(state sm.State, blockExec *sm.BlockExecutor, store *store.BlockStore,
-	fastSync bool) *BlockchainReactor {
+	fastSync bool, async bool, recvBufSize int) *BlockchainReactor {
 
 	if state.LastBlockHeight != store.Height() {
 		panic(fmt.Sprintf("state (%v) and store (%v) height mismatch", state.LastBlockHeight,
@@ -90,7 +90,7 @@ func NewBlockchainReactor(state sm.State, blockExec *sm.BlockExecutor, store *st
 		requestsCh:   requestsCh,
 		errorsCh:     errorsCh,
 	}
-	bcR.BaseReactor = *p2p.NewBaseReactor("BlockchainReactor", bcR)
+	bcR.BaseReactor = *p2p.NewBaseReactor("BlockchainReactor", bcR, async, recvBufSize)
 	return bcR
 }
 
@@ -103,7 +103,13 @@ func (bcR *BlockchainReactor) SetLogger(l log.Logger) {
 // OnStart implements service.Service.
 func (bcR *BlockchainReactor) OnStart() error {
 	if bcR.fastSync {
-		err := bcR.pool.Start()
+		// call BaseReactor's OnStart()
+		err := bcR.BaseReactor.OnStart()
+		if err != nil {
+			return err
+		}
+
+		err = bcR.pool.Start()
 		if err != nil {
 			return err
 		}
diff --git a/blockchain/v0/reactor_test.go b/blockchain/v0/reactor_test.go
index 8aa4d52f4..6aeed8dcc 100644
--- a/blockchain/v0/reactor_test.go
+++ b/blockchain/v0/reactor_test.go
@@ -55,7 +55,9 @@ func newBlockchainReactor(
 	logger log.Logger,
 	genDoc *types.GenesisDoc,
 	privVals []types.PrivValidator,
-	maxBlockHeight int64) BlockchainReactorPair {
+	maxBlockHeight int64,
+	async bool,
+	recvBufSize int) BlockchainReactorPair {
 	if len(privVals) != 1 {
 		panic("only support one validator")
 	}
@@ -125,7 +127,7 @@ func newBlockchainReactor(
 		blockStore.SaveBlock(thisBlock, thisParts, lastCommit)
 	}
 
-	bcReactor := NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+	bcReactor := NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync, async, recvBufSize)
 	bcReactor.SetLogger(logger.With("module", "blockchain"))
 
 	return BlockchainReactorPair{bcReactor, proxyApp}
@@ -140,10 +142,12 @@ func TestNoBlockResponse(t *testing.T) {
 
 	reactorPairs := make([]BlockchainReactorPair, 2)
 
-	reactorPairs[0] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, maxBlockHeight)
-	reactorPairs[1] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0)
+	reactorPairs[0] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, maxBlockHeight,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
+	reactorPairs[1] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 
-	p2p.MakeConnectedSwitches(config.P2P, 2, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, 2, func(i int, s *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("BLOCKCHAIN", reactorPairs[i].reactor)
 		return s
 
@@ -202,7 +206,8 @@ func TestBadBlockStopsPeer(t *testing.T) {
 
 	// Other chain needs a different validator set
 	otherGenDoc, otherPrivVals := randGenesisDoc(1, false, 30)
-	otherChain := newBlockchainReactor(log.TestingLogger(), otherGenDoc, otherPrivVals, maxBlockHeight)
+	otherChain := newBlockchainReactor(log.TestingLogger(), otherGenDoc, otherPrivVals, maxBlockHeight,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 
 	defer func() {
 		err := otherChain.reactor.Stop()
@@ -213,12 +218,17 @@ func TestBadBlockStopsPeer(t *testing.T) {
 
 	reactorPairs := make([]BlockchainReactorPair, 4)
 
-	reactorPairs[0] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, maxBlockHeight)
-	reactorPairs[1] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0)
-	reactorPairs[2] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0)
-	reactorPairs[3] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0)
-
-	switches := p2p.MakeConnectedSwitches(config.P2P, 4, func(i int, s *p2p.Switch) *p2p.Switch {
+	reactorPairs[0] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, maxBlockHeight,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
+	reactorPairs[1] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
+	reactorPairs[2] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
+	reactorPairs[3] = newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
+
+	switches := p2p.MakeConnectedSwitches(config.P2P, 4, func(i int, s *p2p.Switch,
+		config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("BLOCKCHAIN", reactorPairs[i].reactor)
 		return s
 
@@ -254,10 +264,12 @@ func TestBadBlockStopsPeer(t *testing.T) {
 	// race, but can't be easily avoided.
 	reactorPairs[3].reactor.store = otherChain.reactor.store
 
-	lastReactorPair := newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0)
+	lastReactorPair := newBlockchainReactor(log.TestingLogger(), genDoc, privVals, 0,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 	reactorPairs = append(reactorPairs, lastReactorPair)
 
-	switches = append(switches, p2p.MakeConnectedSwitches(config.P2P, 1, func(i int, s *p2p.Switch) *p2p.Switch {
+	switches = append(switches, p2p.MakeConnectedSwitches(config.P2P, 1, func(i int, s *p2p.Switch,
+		config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("BLOCKCHAIN", reactorPairs[len(reactorPairs)-1].reactor)
 		return s
 
diff --git a/blockchain/v1/reactor.go b/blockchain/v1/reactor.go
index 84c47ed5f..9068ba4a3 100644
--- a/blockchain/v1/reactor.go
+++ b/blockchain/v1/reactor.go
@@ -71,7 +71,7 @@ type BlockchainReactor struct {
 
 // NewBlockchainReactor returns new reactor instance.
 func NewBlockchainReactor(state sm.State, blockExec *sm.BlockExecutor, store *store.BlockStore,
-	fastSync bool) *BlockchainReactor {
+	fastSync bool, async bool, recvBufSize int) *BlockchainReactor {
 
 	if state.LastBlockHeight != store.Height() {
 		panic(fmt.Sprintf("state (%v) and store (%v) height mismatch", state.LastBlockHeight,
@@ -99,7 +99,7 @@ func NewBlockchainReactor(state sm.State, blockExec *sm.BlockExecutor, store *st
 	}
 	fsm := NewFSM(startHeight, bcR)
 	bcR.fsm = fsm
-	bcR.BaseReactor = *p2p.NewBaseReactor("BlockchainReactor", bcR)
+	bcR.BaseReactor = *p2p.NewBaseReactor("BlockchainReactor", bcR, async, recvBufSize)
 	// bcR.swReporter = behaviour.NewSwitchReporter(bcR.BaseReactor.Switch)
 
 	return bcR
@@ -140,6 +140,12 @@ func (bcR *BlockchainReactor) SetLogger(l log.Logger) {
 func (bcR *BlockchainReactor) OnStart() error {
 	bcR.swReporter = behaviour.NewSwitchReporter(bcR.BaseReactor.Switch)
 	if bcR.fastSync {
+		// call BaseReactor's OnStart()
+		err := bcR.BaseReactor.OnStart()
+		if err != nil {
+			return err
+		}
+
 		go bcR.poolRoutine()
 	}
 	return nil
diff --git a/blockchain/v1/reactor_test.go b/blockchain/v1/reactor_test.go
index d3d9d817e..5c859c5e5 100644
--- a/blockchain/v1/reactor_test.go
+++ b/blockchain/v1/reactor_test.go
@@ -146,7 +146,8 @@ func newBlockchainReactor(
 		blockStore.SaveBlock(thisBlock, thisParts, lastCommit)
 	}
 
-	bcReactor := NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+	bcReactor := NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync,
+		config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 	bcReactor.SetLogger(logger.With("module", "blockchain"))
 
 	return bcReactor
@@ -160,7 +161,8 @@ func newBlockchainReactorPair(
 	maxBlockHeight int64) BlockchainReactorPair {
 
 	consensusReactor := &consensusReactorTest{}
-	consensusReactor.BaseReactor = *p2p.NewBaseReactor("Consensus reactor", consensusReactor)
+	consensusReactor.BaseReactor = *p2p.NewBaseReactor("Consensus reactor", consensusReactor,
+		config.P2P.RecvAsync, config.P2P.ConsensusRecvBufSize)
 
 	return BlockchainReactorPair{
 		newBlockchainReactor(t, logger, genDoc, privVals, maxBlockHeight),
@@ -193,7 +195,7 @@ func TestFastSyncNoBlockResponse(t *testing.T) {
 	reactorPairs[0] = newBlockchainReactorPair(t, logger, genDoc, privVals, maxBlockHeight)
 	reactorPairs[1] = newBlockchainReactorPair(t, logger, genDoc, privVals, 0)
 
-	p2p.MakeConnectedSwitches(config.P2P, 2, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, 2, func(i int, s *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("BLOCKCHAIN", reactorPairs[i].bcR)
 		s.AddReactor("CONSENSUS", reactorPairs[i].conR)
 		moduleName := fmt.Sprintf("blockchain-%v", i)
@@ -273,7 +275,8 @@ func TestFastSyncBadBlockStopsPeer(t *testing.T) {
 		reactorPairs[i] = newBlockchainReactorPair(t, logger[i], genDoc, privVals, height)
 	}
 
-	switches := p2p.MakeConnectedSwitches(config.P2P, numNodes, func(i int, s *p2p.Switch) *p2p.Switch {
+	switches := p2p.MakeConnectedSwitches(config.P2P, numNodes, func(i int, s *p2p.Switch,
+		config *cfg.P2PConfig) *p2p.Switch {
 		reactorPairs[i].conR.mtx.Lock()
 		s.AddReactor("BLOCKCHAIN", reactorPairs[i].bcR)
 		s.AddReactor("CONSENSUS", reactorPairs[i].conR)
@@ -315,7 +318,8 @@ outerFor:
 	lastReactorPair := newBlockchainReactorPair(t, lastLogger, genDoc, privVals, 0)
 	reactorPairs = append(reactorPairs, lastReactorPair)
 
-	switches = append(switches, p2p.MakeConnectedSwitches(config.P2P, 1, func(i int, s *p2p.Switch) *p2p.Switch {
+	switches = append(switches, p2p.MakeConnectedSwitches(config.P2P, 1, func(i int, s *p2p.Switch,
+		config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("BLOCKCHAIN", reactorPairs[len(reactorPairs)-1].bcR)
 		s.AddReactor("CONSENSUS", reactorPairs[len(reactorPairs)-1].conR)
 		moduleName := fmt.Sprintf("blockchain-%v", len(reactorPairs)-1)
diff --git a/config/config.go b/config/config.go
index a47c1bcf8..a08e26cef 100644
--- a/config/config.go
+++ b/config/config.go
@@ -584,6 +584,16 @@ type P2PConfig struct { //nolint: maligned
 	HandshakeTimeout time.Duration `mapstructure:"handshake_timeout"`
 	DialTimeout      time.Duration `mapstructure:"dial_timeout"`
 
+	// Reactor async receive
+	RecvAsync bool `mapstructure:"recv_async"`
+
+	// Size of receive buffer used in async receiving
+	PexRecvBufSize        int `mapstructure:"pex_recv_buf_size"`
+	EvidenceRecvBufSize   int `mapstructure:"evidence_recv_buf_size"`
+	MempoolRecvBufSize    int `mapstructure:"mempool_recv_buf_size"`
+	ConsensusRecvBufSize  int `mapstructure:"consensus_recv_buf_size"`
+	BlockchainRecvBufSize int `mapstructure:"blockchain_recv_buf_size"`
+
 	// Testing params.
 	// Force dial to fail
 	TestDialFail bool `mapstructure:"test_dial_fail"`
@@ -612,6 +622,12 @@ func DefaultP2PConfig() *P2PConfig {
 		AllowDuplicateIP:             false,
 		HandshakeTimeout:             20 * time.Second,
 		DialTimeout:                  3 * time.Second,
+		RecvAsync:                    true,
+		PexRecvBufSize:               1000,
+		EvidenceRecvBufSize:          1000,
+		MempoolRecvBufSize:           1000,
+		ConsensusRecvBufSize:         1000,
+		BlockchainRecvBufSize:        1000,
 		TestDialFail:                 false,
 		TestFuzz:                     false,
 		TestFuzzConfig:               DefaultFuzzConnConfig(),
diff --git a/config/toml.go b/config/toml.go
index fe797e95b..78ed6a80e 100644
--- a/config/toml.go
+++ b/config/toml.go
@@ -332,6 +332,18 @@ allow_duplicate_ip = {{ .P2P.AllowDuplicateIP }}
 handshake_timeout = "{{ .P2P.HandshakeTimeout }}"
 dial_timeout = "{{ .P2P.DialTimeout }}"
 
+# Sync/async of reactor's receive function
+recv_async = {{ .P2P.RecvAsync }}
+
+# Size of channel buffer of reactor
+pex_recv_buf_size = {{ .P2P.PexRecvBufSize }}
+mempool_recv_buf_size = {{ .P2P.MempoolRecvBufSize }}
+evidence_recv_buf_size = {{ .P2P.EvidenceRecvBufSize }}
+consensus_recv_buf_size = {{ .P2P.ConsensusRecvBufSize }}
+blockchain_recv_buf_size = {{ .P2P.BlockchainRecvBufSize }}
+
+##### mempool configuration options #####
+
 #######################################################
 ###          Mempool Configuration Option          ###
 #######################################################
diff --git a/consensus/byzantine_test.go b/consensus/byzantine_test.go
index 4639d34bd..769941960 100644
--- a/consensus/byzantine_test.go
+++ b/consensus/byzantine_test.go
@@ -9,6 +9,7 @@ import (
 	"testing"
 	"time"
 
+	config2 "github.com/line/ostracon/config"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -101,7 +102,7 @@ func TestByzantinePrevoteEquivocation(t *testing.T) {
 	blocksSubs := make([]types.Subscription, 0)
 	eventBuses := make([]*types.EventBus, nValidators)
 	for i := 0; i < nValidators; i++ {
-		reactors[i] = NewReactor(css[i], true) // so we dont start the consensus states
+		reactors[i] = NewReactor(css[i], true, true, 1000) // so we dont start the consensus states
 		reactors[i].SetLogger(css[i].Logger)
 
 		// eventBus is already started with the cs
@@ -118,7 +119,7 @@ func TestByzantinePrevoteEquivocation(t *testing.T) {
 		}
 	}
 	// make connected switches and start all reactors
-	p2p.MakeConnectedSwitches(config.P2P, nValidators, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, nValidators, func(i int, s *p2p.Switch, config *config2.P2PConfig) *p2p.Switch {
 		s.AddReactor("CONSENSUS", reactors[i])
 		s.SetLogger(reactors[i].conS.Logger.With("module", "p2p"))
 		return s
@@ -297,7 +298,7 @@ func TestByzantineConflictingProposalsWithPartition(t *testing.T) {
 			config.P2P,
 			i,
 			"foo", "1.0.0",
-			func(i int, sw *p2p.Switch) *p2p.Switch {
+			func(i int, sw *p2p.Switch, config *config2.P2PConfig) *p2p.Switch {
 				return sw
 			})
 		switches[i].SetLogger(p2pLogger.With("validator", i))
@@ -331,7 +332,7 @@ func TestByzantineConflictingProposalsWithPartition(t *testing.T) {
 		blocksSubs[i], err = eventBus.Subscribe(context.Background(), testSubscriber, types.EventQueryNewBlock)
 		require.NoError(t, err)
 
-		conR := NewReactor(css[i], true) // so we don't start the consensus states
+		conR := NewReactor(css[i], true, true, 1000) // so we don't start the consensus states
 		conR.SetLogger(logger.With("validator", i))
 		conR.SetEventBus(eventBus)
 
@@ -359,7 +360,7 @@ func TestByzantineConflictingProposalsWithPartition(t *testing.T) {
 		}
 	}()
 
-	p2p.MakeConnectedSwitches(config.P2P, N, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, N, func(i int, s *p2p.Switch, config *config2.P2PConfig) *p2p.Switch {
 		// ignore new switch s, we already made ours
 		switches[i].AddReactor("CONSENSUS", reactors[i])
 		return switches[i]
@@ -552,3 +553,10 @@ func (br *ByzantineReactor) Receive(chID byte, peer p2p.Peer, msgBytes []byte) {
 	br.reactor.Receive(chID, peer, msgBytes)
 }
 func (br *ByzantineReactor) InitPeer(peer p2p.Peer) p2p.Peer { return peer }
+func (br *ByzantineReactor) RecvRoutine() {
+	br.reactor.RecvRoutine()
+}
+
+func (br *ByzantineReactor) GetRecvChan() chan *p2p.BufferedMsg {
+	return br.reactor.GetRecvChan()
+}
diff --git a/consensus/reactor.go b/consensus/reactor.go
index 5d75c09d4..554fb300e 100644
--- a/consensus/reactor.go
+++ b/consensus/reactor.go
@@ -54,13 +54,13 @@ type ReactorOption func(*Reactor)
 
 // NewReactor returns a new Reactor with the given
 // consensusState.
-func NewReactor(consensusState *State, waitSync bool, options ...ReactorOption) *Reactor {
+func NewReactor(consensusState *State, fastSync bool, async bool, recvBufSize int, options ...ReactorOption) *Reactor {
 	conR := &Reactor{
 		conS:     consensusState,
-		waitSync: waitSync,
+		waitSync: fastSync,
 		Metrics:  NopMetrics(),
 	}
-	conR.BaseReactor = *p2p.NewBaseReactor("Consensus", conR)
+	conR.BaseReactor = *p2p.NewBaseReactor("Consensus", conR, async, recvBufSize)
 
 	for _, option := range options {
 		option(conR)
@@ -74,6 +74,12 @@ func NewReactor(consensusState *State, waitSync bool, options ...ReactorOption)
 func (conR *Reactor) OnStart() error {
 	conR.Logger.Info("Reactor ", "waitSync", conR.WaitSync())
 
+	// call BaseReactor's OnStart()
+	err := conR.BaseReactor.OnStart()
+	if err != nil {
+		return err
+	}
+
 	// start routine that computes peer statistics for evaluating peer quality
 	go conR.peerStatsRoutine()
 
diff --git a/consensus/reactor_test.go b/consensus/reactor_test.go
index 845e20e99..208bc1e23 100644
--- a/consensus/reactor_test.go
+++ b/consensus/reactor_test.go
@@ -54,7 +54,7 @@ func startConsensusNet(t *testing.T, css []*State, n int) (
 	for i := 0; i < n; i++ {
 		/*logger, err := tmflags.ParseLogLevel("consensus:info,*:error", logger, "info")
 		if err != nil {	t.Fatal(err)}*/
-		reactors[i] = NewReactor(css[i], true) // so we dont start the consensus states
+		reactors[i] = NewReactor(css[i], true, true, 1000) // so we dont start the consensus states
 		reactors[i].SetLogger(css[i].Logger)
 
 		// eventBus is already started with the cs
@@ -73,7 +73,7 @@ func startConsensusNet(t *testing.T, css []*State, n int) (
 		}
 	}
 	// make connected switches and start all reactors
-	p2p.MakeConnectedSwitches(config.P2P, n, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, n, func(i int, s *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("CONSENSUS", reactors[i])
 		s.SetLogger(reactors[i].conS.Logger.With("module", "p2p"))
 		return s
diff --git a/docs/tendermint-core/configuration.md b/docs/tendermint-core/configuration.md
index d13574884..8c12ab805 100644
--- a/docs/tendermint-core/configuration.md
+++ b/docs/tendermint-core/configuration.md
@@ -258,9 +258,17 @@ allow_duplicate_ip = false
 handshake_timeout = "20s"
 dial_timeout = "3s"
 
-#######################################################
-###          Mempool Configurattion Option          ###
-#######################################################
+# Sync/async of reactor's receive function
+recv_async = true
+
+# Size of channel buffer of reactor
+pex_recv_buf_size = 1000
+mempool_recv_buf_size = 1000
+evidence_recv_buf_size = 1000
+consensus_recv_buf_size = 1000
+blockchain_recv_buf_size = 1000
+
+##### mempool configuration options #####
 [mempool]
 
 recheck = true
diff --git a/evidence/reactor.go b/evidence/reactor.go
index 6c97bb1ae..d4f1ce941 100644
--- a/evidence/reactor.go
+++ b/evidence/reactor.go
@@ -33,11 +33,11 @@ type Reactor struct {
 }
 
 // NewReactor returns a new Reactor with the given config and evpool.
-func NewReactor(evpool *Pool) *Reactor {
+func NewReactor(evpool *Pool, async bool, recvBufSize int) *Reactor {
 	evR := &Reactor{
 		evpool: evpool,
 	}
-	evR.BaseReactor = *p2p.NewBaseReactor("Evidence", evR)
+	evR.BaseReactor = *p2p.NewBaseReactor("Evidence", evR, async, recvBufSize)
 	return evR
 }
 
diff --git a/evidence/reactor_test.go b/evidence/reactor_test.go
index 89e3f6a69..5bd73e12b 100644
--- a/evidence/reactor_test.go
+++ b/evidence/reactor_test.go
@@ -188,6 +188,8 @@ func TestReactorsGossipNoCommittedEvidence(t *testing.T) {
 }
 
 func TestReactorBroadcastEvidenceMemoryLeak(t *testing.T) {
+	config := cfg.TestConfig()
+
 	evidenceTime := time.Date(2019, 1, 1, 0, 0, 0, 0, time.UTC)
 	evidenceDB := memdb.NewDB()
 	blockStore := &mocks.BlockStore{}
@@ -215,7 +217,7 @@ func TestReactorBroadcastEvidenceMemoryLeak(t *testing.T) {
 	p.On("ID").Return("ABC")
 	p.On("String").Return("mock")
 
-	r := evidence.NewReactor(pool)
+	r := evidence.NewReactor(pool, config.P2P.RecvAsync, config.P2P.EvidenceRecvBufSize)
 	r.SetLogger(log.TestingLogger())
 	r.AddPeer(p)
 
@@ -256,11 +258,11 @@ func makeAndConnectReactorsAndPools(config *cfg.Config, stateStores []sm.Store)
 			panic(err)
 		}
 		pools[i] = pool
-		reactors[i] = evidence.NewReactor(pool)
+		reactors[i] = evidence.NewReactor(pool, config.P2P.RecvAsync, config.P2P.EvidenceRecvBufSize)
 		reactors[i].SetLogger(logger.With("validator", i))
 	}
 
-	p2p.MakeConnectedSwitches(config.P2P, N, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, N, func(i int, s *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("EVIDENCE", reactors[i])
 		return s
 
diff --git a/mempool/reactor.go b/mempool/reactor.go
index 761f3a53a..b93cb588c 100644
--- a/mempool/reactor.go
+++ b/mempool/reactor.go
@@ -101,13 +101,13 @@ func newMempoolIDs() *mempoolIDs {
 }
 
 // NewReactor returns a new Reactor with the given config and mempool.
-func NewReactor(config *cfg.MempoolConfig, mempool *CListMempool) *Reactor {
+func NewReactor(config *cfg.MempoolConfig, async bool, recvBufSize int, mempool *CListMempool) *Reactor {
 	memR := &Reactor{
 		config:  config,
 		mempool: mempool,
 		ids:     newMempoolIDs(),
 	}
-	memR.BaseReactor = *p2p.NewBaseReactor("Mempool", memR)
+	memR.BaseReactor = *p2p.NewBaseReactor("Mempool", memR, async, recvBufSize)
 	return memR
 }
 
@@ -125,6 +125,12 @@ func (memR *Reactor) SetLogger(l log.Logger) {
 
 // OnStart implements p2p.BaseReactor.
 func (memR *Reactor) OnStart() error {
+	// call BaseReactor's OnStart()
+	err := memR.BaseReactor.OnStart()
+	if err != nil {
+		return nil
+	}
+
 	if !memR.config.Broadcast {
 		memR.Logger.Info("Tx broadcasting is disabled")
 	}
diff --git a/mempool/reactor_test.go b/mempool/reactor_test.go
index 5ba7bfcda..c96f71bda 100644
--- a/mempool/reactor_test.go
+++ b/mempool/reactor_test.go
@@ -307,11 +307,12 @@ func makeAndConnectReactors(config *cfg.Config, n int) []*Reactor {
 		mempool, cleanup := newMempoolWithApp(cc)
 		defer cleanup()
 
-		reactors[i] = NewReactor(config.Mempool, mempool) // so we dont start the consensus states
+		// so we dont start the consensus states
+		reactors[i] = NewReactor(config.Mempool, config.P2P.RecvAsync, config.P2P.MempoolRecvBufSize, mempool)
 		reactors[i].SetLogger(logger.With("validator", i))
 	}
 
-	p2p.MakeConnectedSwitches(config.P2P, n, func(i int, s *p2p.Switch) *p2p.Switch {
+	p2p.MakeConnectedSwitches(config.P2P, n, func(i int, s *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch {
 		s.AddReactor("MEMPOOL", reactors[i])
 		return s
 
diff --git a/node/node.go b/node/node.go
index a4c49493b..a074d54b0 100644
--- a/node/node.go
+++ b/node/node.go
@@ -325,7 +325,7 @@ func createMempoolAndMempoolReactor(config *cfg.Config, proxyApp proxy.AppConns,
 		mempl.WithPreCheck(sm.TxPreCheck(state)),
 	)
 	mempoolLogger := logger.With("module", "mempool")
-	mempoolReactor := mempl.NewReactor(config.Mempool, mempool)
+	mempoolReactor := mempl.NewReactor(config.Mempool, config.P2P.RecvAsync, config.P2P.MempoolRecvBufSize, mempool)
 	mempoolReactor.SetLogger(mempoolLogger)
 
 	if config.Consensus.WaitForTxs() {
@@ -346,7 +346,7 @@ func createEvidenceReactor(config *cfg.Config, dbProvider DBProvider,
 	if err != nil {
 		return nil, nil, err
 	}
-	evidenceReactor := evidence.NewReactor(evidencePool)
+	evidenceReactor := evidence.NewReactor(evidencePool, config.P2P.RecvAsync, config.P2P.EvidenceRecvBufSize)
 	evidenceReactor.SetLogger(evidenceLogger)
 	return evidenceReactor, evidencePool, nil
 }
@@ -360,9 +360,11 @@ func createBlockchainReactor(config *cfg.Config,
 
 	switch config.FastSync.Version {
 	case "v0":
-		bcReactor = bcv0.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+		bcReactor = bcv0.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync,
+			config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 	case "v1":
-		bcReactor = bcv1.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+		bcReactor = bcv1.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync,
+			config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 	case "v2":
 		bcReactor = bcv2.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
 	default:
@@ -398,7 +400,8 @@ func createConsensusReactor(config *cfg.Config,
 	if privValidator != nil {
 		consensusState.SetPrivValidator(privValidator)
 	}
-	consensusReactor := cs.NewReactor(consensusState, waitSync, cs.ReactorMetrics(csMetrics))
+	consensusReactor := cs.NewReactor(consensusState, waitSync, config.P2P.RecvAsync, config.P2P.ConsensusRecvBufSize,
+		cs.ReactorMetrics(csMetrics))
 	consensusReactor.SetLogger(consensusLogger)
 	// services which will be publishing and/or subscribing for messages (events)
 	// consensusReactor will set it on consensusState and blockExecutor
@@ -540,6 +543,7 @@ func createPEXReactorAndAddToSwitch(addrBook pex.AddrBook, config *cfg.Config,
 
 	// TODO persistent peers ? so we can have their DNS addrs saved
 	pexReactor := pex.NewReactor(addrBook,
+		config.P2P.RecvAsync,
 		&pex.ReactorConfig{
 			Seeds:    splitAndTrimEmpty(config.P2P.Seeds, ",", " "),
 			SeedMode: config.P2P.SeedMode,
@@ -550,6 +554,7 @@ func createPEXReactorAndAddToSwitch(addrBook pex.AddrBook, config *cfg.Config,
 			// https://github.com/tendermint/tendermint/issues/3523
 			SeedDisconnectWaitPeriod:     28 * time.Hour,
 			PersistentPeersMaxDialPeriod: config.P2P.PersistentPeersMaxDialPeriod,
+			RecvBufSize:                  config.P2P.PexRecvBufSize,
 		})
 	pexReactor.SetLogger(logger.With("module", "pex"))
 	sw.AddReactor("PEX", pexReactor)
diff --git a/p2p/base_reactor.go b/p2p/base_reactor.go
index f3721e52b..9ffc530b5 100644
--- a/p2p/base_reactor.go
+++ b/p2p/base_reactor.go
@@ -45,6 +45,12 @@ type Reactor interface {
 	//
 	// CONTRACT: msgBytes are not nil.
 	Receive(chID byte, peer Peer, msgBytes []byte)
+
+	// receive async version
+	GetRecvChan() chan *BufferedMsg
+
+	// receive routine per reactor
+	RecvRoutine()
 }
 
 //--------------------------------------
@@ -52,13 +58,20 @@ type Reactor interface {
 type BaseReactor struct {
 	service.BaseService // Provides Start, Stop, .Quit
 	Switch              *Switch
+	recvMsgBuf          chan *BufferedMsg
+	impl                Reactor
 }
 
-func NewBaseReactor(name string, impl Reactor) *BaseReactor {
-	return &BaseReactor{
+func NewBaseReactor(name string, impl Reactor, async bool, recvBufSize int) *BaseReactor {
+	baseReactor := &BaseReactor{
 		BaseService: *service.NewBaseService(nil, name, impl),
 		Switch:      nil,
+		impl:        impl,
+	}
+	if async {
+		baseReactor.recvMsgBuf = make(chan *BufferedMsg, recvBufSize)
 	}
+	return baseReactor
 }
 
 func (br *BaseReactor) SetSwitch(sw *Switch) {
@@ -69,3 +82,29 @@ func (*BaseReactor) AddPeer(peer Peer)                             {}
 func (*BaseReactor) RemovePeer(peer Peer, reason interface{})      {}
 func (*BaseReactor) Receive(chID byte, peer Peer, msgBytes []byte) {}
 func (*BaseReactor) InitPeer(peer Peer) Peer                       { return peer }
+
+func (br *BaseReactor) OnStart() error {
+	if br.recvMsgBuf != nil {
+		// if it is async mode it starts RecvRoutine()
+		go br.RecvRoutine()
+	}
+	return nil
+}
+
+func (br *BaseReactor) RecvRoutine() {
+	for {
+		select {
+		case msg := <-br.recvMsgBuf:
+			br.impl.Receive(msg.ChID, msg.Peer, msg.Msg)
+		case <-br.Quit():
+			return
+		}
+	}
+}
+
+func (br *BaseReactor) GetRecvChan() chan *BufferedMsg {
+	if br.recvMsgBuf == nil {
+		panic("It's not async reactor, but GetRecvChan() is called ")
+	}
+	return br.recvMsgBuf
+}
diff --git a/p2p/conn/connection.go b/p2p/conn/connection.go
index 15e9dc1be..9213c8c45 100644
--- a/p2p/conn/connection.go
+++ b/p2p/conn/connection.go
@@ -45,6 +45,7 @@ const (
 	defaultSendTimeout         = 10 * time.Second
 	defaultPingInterval        = 60 * time.Second
 	defaultPongTimeout         = 45 * time.Second
+	defaultRecvAsync           = true
 )
 
 type receiveCbFunc func(chID byte, msgBytes []byte)
@@ -133,6 +134,9 @@ type MConnConfig struct {
 
 	// Maximum wait time for pongs
 	PongTimeout time.Duration `mapstructure:"pong_timeout"`
+
+	// Action method of reactor's receive function
+	RecvAsync bool `mapstructure:"recv_async"`
 }
 
 // DefaultMConnConfig returns the default config.
@@ -144,6 +148,7 @@ func DefaultMConnConfig() MConnConfig {
 		FlushThrottle:           defaultFlushThrottle,
 		PingInterval:            defaultPingInterval,
 		PongTimeout:             defaultPongTimeout,
+		RecvAsync:               defaultRecvAsync,
 	}
 }
 
diff --git a/p2p/metrics.go b/p2p/metrics.go
index 675dd9c7c..5eeaf37b4 100644
--- a/p2p/metrics.go
+++ b/p2p/metrics.go
@@ -25,6 +25,10 @@ type Metrics struct {
 	PeerPendingSendBytes metrics.Gauge
 	// Number of transactions submitted by each peer.
 	NumTxs metrics.Gauge
+	// Number of abandoned peer messages
+	NumAbandonedPeerMsgs metrics.Counter
+	// Number of pooled peer messages
+	NumPooledPeerMsgs metrics.Gauge
 }
 
 // PrometheusMetrics returns Metrics build using Prometheus client library.
@@ -66,6 +70,18 @@ func PrometheusMetrics(namespace string, labelsAndValues ...string) *Metrics {
 			Name:      "num_txs",
 			Help:      "Number of transactions submitted by each peer.",
 		}, append(labels, "peer_id")).With(labelsAndValues...),
+		NumAbandonedPeerMsgs: prometheus.NewCounterFrom(stdprometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: MetricsSubsystem,
+			Name:      "num_abandoned_peer_msgs",
+			Help:      "Number of peer messages abandoned because of full channel",
+		}, append(labels, "peer_id", "chID")).With(labelsAndValues...),
+		NumPooledPeerMsgs: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: MetricsSubsystem,
+			Name:      "num_pooled_peer_msgs",
+			Help:      "Number of peer messages pooled currently",
+		}, append(labels, "peer_id", "chID")).With(labelsAndValues...),
 	}
 }
 
@@ -77,5 +93,7 @@ func NopMetrics() *Metrics {
 		PeerSendBytesTotal:    discard.NewCounter(),
 		PeerPendingSendBytes:  discard.NewGauge(),
 		NumTxs:                discard.NewGauge(),
+		NumAbandonedPeerMsgs:  discard.NewCounter(),
+		NumPooledPeerMsgs:     discard.NewGauge(),
 	}
 }
diff --git a/p2p/mock/reactor.go b/p2p/mock/reactor.go
index 8d1b5ee68..cb80a924a 100644
--- a/p2p/mock/reactor.go
+++ b/p2p/mock/reactor.go
@@ -12,7 +12,7 @@ type Reactor struct {
 
 func NewReactor() *Reactor {
 	r := &Reactor{}
-	r.BaseReactor = *p2p.NewBaseReactor("Mock-PEX", r)
+	r.BaseReactor = *p2p.NewBaseReactor("Mock-PEX", r, true, 1000)
 	r.SetLogger(log.TestingLogger())
 	return r
 }
diff --git a/p2p/peer.go b/p2p/peer.go
index ae772eb38..454520b6b 100644
--- a/p2p/peer.go
+++ b/p2p/peer.go
@@ -41,6 +41,12 @@ type Peer interface {
 	Get(string) interface{}
 }
 
+type BufferedMsg struct {
+	ChID byte
+	Peer Peer
+	Msg  []byte
+}
+
 //----------------------------------------------------------
 
 // peerConn contains the raw connection and its config.
@@ -387,7 +393,25 @@ func createMConnection(
 			"chID", fmt.Sprintf("%#x", chID),
 		}
 		p.metrics.PeerReceiveBytesTotal.With(labels...).Add(float64(len(msgBytes)))
-		reactor.Receive(chID, p, msgBytes)
+		if config.RecvAsync {
+			ch := reactor.GetRecvChan()
+			p.metrics.NumPooledPeerMsgs.With(labels...).Set(float64(len(ch)))
+			// we must use copied msgBytes
+			// because msgBytes is on socket receive buffer yet so reactor can read it concurrently
+			copied := make([]byte, len(msgBytes))
+			copy(copied, msgBytes)
+			select {
+			case ch <- &BufferedMsg{
+				ChID: chID,
+				Peer: p,
+				Msg:  copied}:
+			default:
+				// if the channel is full, we abandon this message
+				p.metrics.NumAbandonedPeerMsgs.With(labels...).Add(1)
+			}
+		} else {
+			reactor.Receive(chID, p, msgBytes)
+		}
 	}
 
 	onError := func(r interface{}) {
diff --git a/p2p/peer_test.go b/p2p/peer_test.go
index 7e973a614..5f6cb5473 100644
--- a/p2p/peer_test.go
+++ b/p2p/peer_test.go
@@ -81,7 +81,7 @@ func createOutboundPeerAndPerformHandshake(
 	chDescs := []*tmconn.ChannelDescriptor{
 		{ID: testCh, Priority: 1},
 	}
-	reactorsByCh := map[byte]Reactor{testCh: NewTestReactor(chDescs, true)}
+	reactorsByCh := map[byte]Reactor{testCh: NewTestReactor(chDescs, true, 1000, true)}
 	pk := ed25519.GenPrivKey()
 	pc, err := testOutboundPeerConn(addr, config, false, pk)
 	if err != nil {
diff --git a/p2p/pex/pex_reactor.go b/p2p/pex/pex_reactor.go
index ac88f5f19..4008e6dc5 100644
--- a/p2p/pex/pex_reactor.go
+++ b/p2p/pex/pex_reactor.go
@@ -122,6 +122,9 @@ type ReactorConfig struct {
 	// Seeds is a list of addresses reactor may use
 	// if it can't connect to peers in the addrbook.
 	Seeds []string
+
+	// Receive channel buffer size
+	RecvBufSize int
 }
 
 type _attemptsToDial struct {
@@ -130,7 +133,7 @@ type _attemptsToDial struct {
 }
 
 // NewReactor creates new PEX reactor.
-func NewReactor(b AddrBook, config *ReactorConfig) *Reactor {
+func NewReactor(b AddrBook, async bool, config *ReactorConfig) *Reactor {
 	r := &Reactor{
 		book:                 b,
 		config:               config,
@@ -139,13 +142,19 @@ func NewReactor(b AddrBook, config *ReactorConfig) *Reactor {
 		lastReceivedRequests: cmap.NewCMap(),
 		crawlPeerInfos:       make(map[p2p.ID]crawlPeerInfo),
 	}
-	r.BaseReactor = *p2p.NewBaseReactor("PEX", r)
+	r.BaseReactor = *p2p.NewBaseReactor("PEX", r, async, config.RecvBufSize)
 	return r
 }
 
 // OnStart implements BaseService
 func (r *Reactor) OnStart() error {
-	err := r.book.Start()
+	// call BaseReactor's OnStart()
+	err := r.BaseReactor.OnStart()
+	if err != nil {
+		return err
+	}
+
+	err = r.book.Start()
 	if err != nil && err != service.ErrAlreadyStarted {
 		return err
 	}
@@ -166,6 +175,7 @@ func (r *Reactor) OnStart() error {
 	} else {
 		go r.ensurePeersRoutine()
 	}
+
 	return nil
 }
 
diff --git a/p2p/pex/pex_reactor_test.go b/p2p/pex/pex_reactor_test.go
index 37b7f6ffe..b029f3d77 100644
--- a/p2p/pex/pex_reactor_test.go
+++ b/p2p/pex/pex_reactor_test.go
@@ -82,14 +82,15 @@ func TestPEXReactorRunning(t *testing.T) {
 
 	// create switches
 	for i := 0; i < N; i++ {
-		switches[i] = p2p.MakeSwitch(cfg, i, "testing", "123.123.123", func(i int, sw *p2p.Switch) *p2p.Switch {
+		switches[i] = p2p.MakeSwitch(cfg, i, "testing", "123.123.123", func(i int, sw *p2p.Switch,
+			config *config.P2PConfig) *p2p.Switch {
 			books[i] = NewAddrBook(filepath.Join(dir, fmt.Sprintf("addrbook%d.json", i)), false)
 			books[i].SetLogger(logger.With("pex", i))
 			sw.SetAddrBook(books[i])
 
 			sw.SetLogger(logger.With("pex", i))
 
-			r := NewReactor(books[i], &ReactorConfig{})
+			r := NewReactor(books[i], config.RecvAsync, &ReactorConfig{})
 			r.SetLogger(logger.With("pex", i))
 			r.SetEnsurePeersPeriod(250 * time.Millisecond)
 			sw.AddReactor("pex", r)
@@ -418,19 +419,20 @@ func TestPEXReactorSeedModeFlushStop(t *testing.T) {
 
 	// create switches
 	for i := 0; i < N; i++ {
-		switches[i] = p2p.MakeSwitch(cfg, i, "testing", "123.123.123", func(i int, sw *p2p.Switch) *p2p.Switch {
+		switches[i] = p2p.MakeSwitch(cfg, i, "testing", "123.123.123", func(i int, sw *p2p.Switch,
+			config *config.P2PConfig) *p2p.Switch {
 			books[i] = NewAddrBook(filepath.Join(dir, fmt.Sprintf("addrbook%d.json", i)), false)
 			books[i].SetLogger(logger.With("pex", i))
 			sw.SetAddrBook(books[i])
 
 			sw.SetLogger(logger.With("pex", i))
 
-			config := &ReactorConfig{}
+			pexConfig := &ReactorConfig{}
 			if i == 0 {
 				// first one is a seed node
-				config = &ReactorConfig{SeedMode: true}
+				pexConfig = &ReactorConfig{SeedMode: true}
 			}
-			r := NewReactor(books[i], config)
+			r := NewReactor(books[i], config.RecvAsync, pexConfig)
 			r.SetLogger(logger.With("pex", i))
 			r.SetEnsurePeersPeriod(250 * time.Millisecond)
 			sw.AddReactor("pex", r)
@@ -577,13 +579,13 @@ func assertPeersWithTimeout(
 }
 
 // Creates a peer with the provided config
-func testCreatePeerWithConfig(dir string, id int, config *ReactorConfig) *p2p.Switch {
+func testCreatePeerWithConfig(dir string, id int, pexConfig *ReactorConfig) *p2p.Switch {
 	peer := p2p.MakeSwitch(
 		cfg,
 		id,
 		"127.0.0.1",
 		"123.123.123",
-		func(i int, sw *p2p.Switch) *p2p.Switch {
+		func(i int, sw *p2p.Switch, config *config.P2PConfig) *p2p.Switch {
 			book := NewAddrBook(filepath.Join(dir, fmt.Sprintf("addrbook%d.json", id)), false)
 			book.SetLogger(log.TestingLogger())
 			sw.SetAddrBook(book)
@@ -592,7 +594,8 @@ func testCreatePeerWithConfig(dir string, id int, config *ReactorConfig) *p2p.Sw
 
 			r := NewReactor(
 				book,
-				config,
+				config.RecvAsync,
+				pexConfig,
 			)
 			r.SetLogger(log.TestingLogger())
 			sw.AddReactor("pex", r)
@@ -615,7 +618,7 @@ func testCreateSeed(dir string, id int, knownAddrs, srcAddrs []*p2p.NetAddress)
 		id,
 		"127.0.0.1",
 		"123.123.123",
-		func(i int, sw *p2p.Switch) *p2p.Switch {
+		func(i int, sw *p2p.Switch, config *config.P2PConfig) *p2p.Switch {
 			book := NewAddrBook(filepath.Join(dir, "addrbookSeed.json"), false)
 			book.SetLogger(log.TestingLogger())
 			for j := 0; j < len(knownAddrs); j++ {
@@ -626,7 +629,7 @@ func testCreateSeed(dir string, id int, knownAddrs, srcAddrs []*p2p.NetAddress)
 
 			sw.SetLogger(log.TestingLogger())
 
-			r := NewReactor(book, &ReactorConfig{})
+			r := NewReactor(book, config.RecvAsync, &ReactorConfig{})
 			r.SetLogger(log.TestingLogger())
 			sw.AddReactor("pex", r)
 			return sw
@@ -653,7 +656,7 @@ func createReactor(conf *ReactorConfig) (r *Reactor, book AddrBook) {
 	book = NewAddrBook(filepath.Join(dir, "addrbook.json"), true)
 	book.SetLogger(log.TestingLogger())
 
-	r = NewReactor(book, conf)
+	r = NewReactor(book, cfg.RecvAsync, conf)
 	r.SetLogger(log.TestingLogger())
 	return
 }
@@ -667,7 +670,8 @@ func teardownReactor(book AddrBook) {
 }
 
 func createSwitchAndAddReactors(reactors ...p2p.Reactor) *p2p.Switch {
-	sw := p2p.MakeSwitch(cfg, 0, "127.0.0.1", "123.123.123", func(i int, sw *p2p.Switch) *p2p.Switch { return sw })
+	sw := p2p.MakeSwitch(cfg, 0, "127.0.0.1", "123.123.123",
+		func(i int, sw *p2p.Switch, config *config.P2PConfig) *p2p.Switch { return sw })
 	sw.SetLogger(log.TestingLogger())
 	for _, r := range reactors {
 		sw.AddReactor(r.String(), r)
diff --git a/p2p/switch.go b/p2p/switch.go
index 5bc3bbe7c..57b7fcf5d 100644
--- a/p2p/switch.go
+++ b/p2p/switch.go
@@ -37,6 +37,7 @@ func MConnConfig(cfg *config.P2PConfig) conn.MConnConfig {
 	mConfig.SendRate = cfg.SendRate
 	mConfig.RecvRate = cfg.RecvRate
 	mConfig.MaxPacketMsgPayloadSize = cfg.MaxPacketMsgPayloadSize
+	mConfig.RecvAsync = cfg.RecvAsync
 	return mConfig
 }
 
diff --git a/p2p/switch_test.go b/p2p/switch_test.go
index cba3beb8f..27b8115d0 100644
--- a/p2p/switch_test.go
+++ b/p2p/switch_test.go
@@ -51,13 +51,13 @@ type TestReactor struct {
 	msgsReceived map[byte][]PeerMessage
 }
 
-func NewTestReactor(channels []*conn.ChannelDescriptor, logMessages bool) *TestReactor {
+func NewTestReactor(channels []*conn.ChannelDescriptor, async bool, recvBufSize int, logMessages bool) *TestReactor {
 	tr := &TestReactor{
 		channels:     channels,
 		logMessages:  logMessages,
 		msgsReceived: make(map[byte][]PeerMessage),
 	}
-	tr.BaseReactor = *NewBaseReactor("TestReactor", tr)
+	tr.BaseReactor = *NewBaseReactor("TestReactor", tr, async, recvBufSize)
 	tr.SetLogger(log.TestingLogger())
 	return tr
 }
@@ -90,13 +90,13 @@ func (tr *TestReactor) getMsgs(chID byte) []PeerMessage {
 
 // convenience method for creating two switches connected to each other.
 // XXX: note this uses net.Pipe and not a proper TCP conn
-func MakeSwitchPair(t testing.TB, initSwitch func(int, *Switch) *Switch) (*Switch, *Switch) {
+func MakeSwitchPair(t testing.TB, initSwitch func(int, *Switch, *config.P2PConfig) *Switch) (*Switch, *Switch) {
 	// Create two switches that will be interconnected.
 	switches := MakeConnectedSwitches(cfg, 2, initSwitch, Connect2Switches)
 	return switches[0], switches[1]
 }
 
-func initSwitchFunc(i int, sw *Switch) *Switch {
+func initSwitchFunc(i int, sw *Switch, config *config.P2PConfig) *Switch {
 	sw.SetAddrBook(&AddrBookMock{
 		Addrs:    make(map[string]struct{}),
 		OurAddrs: make(map[string]struct{})})
@@ -105,11 +105,11 @@ func initSwitchFunc(i int, sw *Switch) *Switch {
 	sw.AddReactor("foo", NewTestReactor([]*conn.ChannelDescriptor{
 		{ID: byte(0x00), Priority: 10},
 		{ID: byte(0x01), Priority: 10},
-	}, true))
+	}, config.RecvAsync, 1000, true))
 	sw.AddReactor("bar", NewTestReactor([]*conn.ChannelDescriptor{
 		{ID: byte(0x02), Priority: 10},
 		{ID: byte(0x03), Priority: 10},
-	}, true))
+	}, config.RecvAsync, 1000, true))
 
 	return sw
 }
@@ -415,13 +415,13 @@ func TestSwitchStopPeerForError(t *testing.T) {
 	p2pMetrics := PrometheusMetrics(namespace)
 
 	// make two connected switches
-	sw1, sw2 := MakeSwitchPair(t, func(i int, sw *Switch) *Switch {
+	sw1, sw2 := MakeSwitchPair(t, func(i int, sw *Switch, config *config.P2PConfig) *Switch {
 		// set metrics on sw1
 		if i == 0 {
 			opt := WithMetrics(p2pMetrics)
 			opt(sw)
 		}
-		return initSwitchFunc(i, sw)
+		return initSwitchFunc(i, sw, config)
 	})
 
 	assert.Equal(t, len(sw1.Peers().List()), 1)
@@ -747,13 +747,13 @@ func (r *mockReactor) InitCalledBeforeRemoveFinished() bool {
 func TestSwitchInitPeerIsNotCalledBeforeRemovePeer(t *testing.T) {
 	// make reactor
 	reactor := &mockReactor{}
-	reactor.BaseReactor = NewBaseReactor("mockReactor", reactor)
+	reactor.BaseReactor = NewBaseReactor("mockReactor", reactor, true, 1000)
 
 	// make switch
-	sw := MakeSwitch(cfg, 1, "testing", "123.123.123", func(i int, sw *Switch) *Switch {
+	sw := MakeSwitch(cfg, 1, "testing", "123.123.123", func(i int, sw *Switch, config *config.P2PConfig) *Switch {
 		sw.AddReactor("mock", reactor)
 		return sw
-	})
+	}) // mock reactor uses 1000 chan buffer
 	err := sw.Start()
 	require.NoError(t, err)
 	t.Cleanup(func() {
@@ -789,16 +789,16 @@ func TestSwitchInitPeerIsNotCalledBeforeRemovePeer(t *testing.T) {
 }
 
 func BenchmarkSwitchBroadcast(b *testing.B) {
-	s1, s2 := MakeSwitchPair(b, func(i int, sw *Switch) *Switch {
+	s1, s2 := MakeSwitchPair(b, func(i int, sw *Switch, config *config.P2PConfig) *Switch {
 		// Make bar reactors of bar channels each
 		sw.AddReactor("foo", NewTestReactor([]*conn.ChannelDescriptor{
 			{ID: byte(0x00), Priority: 10},
 			{ID: byte(0x01), Priority: 10},
-		}, false))
+		}, config.RecvAsync, 1000, false))
 		sw.AddReactor("bar", NewTestReactor([]*conn.ChannelDescriptor{
 			{ID: byte(0x02), Priority: 10},
 			{ID: byte(0x03), Priority: 10},
-		}, false))
+		}, config.RecvAsync, 1000, false))
 		return sw
 	})
 
@@ -836,3 +836,125 @@ func BenchmarkSwitchBroadcast(b *testing.B) {
 
 	b.Logf("success: %v, failure: %v", numSuccess, numFailure)
 }
+
+type NormalReactor struct {
+	BaseReactor
+	channels []*conn.ChannelDescriptor
+	msgChan  chan []byte
+}
+
+func NewNormalReactor(channels []*conn.ChannelDescriptor, async bool, recvBufSize int) *NormalReactor {
+	nr := &NormalReactor{
+		channels: channels,
+	}
+	nr.BaseReactor = *NewBaseReactor("NormalReactor", nr, async, recvBufSize)
+	nr.msgChan = make(chan []byte)
+	nr.SetLogger(log.TestingLogger())
+	return nr
+}
+
+func (nr *NormalReactor) GetChannels() []*conn.ChannelDescriptor {
+	return nr.channels
+}
+
+func (nr *NormalReactor) AddPeer(peer Peer) {}
+
+func (nr *NormalReactor) RemovePeer(peer Peer, reason interface{}) {}
+
+func (nr *NormalReactor) Receive(chID byte, peer Peer, msgBytes []byte) {
+	nr.msgChan <- msgBytes
+}
+
+type BlockedReactor struct {
+	BaseReactor
+	channels []*conn.ChannelDescriptor
+	waitChan chan int
+}
+
+func NewBlockedReactor(channels []*conn.ChannelDescriptor, async bool, recvBufSize int) *BlockedReactor {
+	br := &BlockedReactor{
+		channels: channels,
+	}
+	br.BaseReactor = *NewBaseReactor("BlockedReactor", br, async, recvBufSize)
+	br.waitChan = make(chan int, 1)
+	br.SetLogger(log.TestingLogger())
+	return br
+}
+
+func (br *BlockedReactor) GetChannels() []*conn.ChannelDescriptor {
+	return br.channels
+}
+
+func (br *BlockedReactor) AddPeer(peer Peer) {}
+
+func (br *BlockedReactor) RemovePeer(peer Peer, reason interface{}) {}
+
+func (br *BlockedReactor) Receive(chID byte, peer Peer, msgBytes []byte) {
+	<-br.waitChan
+}
+
+const (
+	reactorNameNormal  = "normal"
+	reactorNameBlocked = "blocked"
+)
+
+func TestSyncReactor(t *testing.T) {
+	cfg.RecvAsync = false
+	s1, s2 := MakeSwitchPair(t, getInitSwitchFunc(0))
+	defer s1.Stop() //nolint:errcheck
+	defer s2.Stop() //nolint:errcheck
+
+	normalReactor := s2.Reactor(reactorNameNormal).(*NormalReactor)
+	blockedReactor := s2.Reactor(reactorNameBlocked).(*BlockedReactor)
+	s1.Broadcast(0x01, []byte{1})      // the message for blocked reactor is first
+	time.Sleep(time.Millisecond * 200) // to make order among messages
+	s1.Broadcast(0x00, []byte{0})      // and then second message is for normal reactor
+
+	select {
+	case <-normalReactor.msgChan:
+		assert.Fail(t, "blocked reactor is not blocked")
+	case <-time.After(time.Second * 1):
+		assert.True(t, true, "blocked reactor is blocked: OK")
+	}
+
+	blockedReactor.waitChan <- 1 // release blocked reactor
+	msg := <-normalReactor.msgChan
+	assert.True(t, bytes.Equal(msg, []byte{0}))
+}
+
+func TestAsyncReactor(t *testing.T) {
+	cfg.RecvAsync = true
+	s1, s2 := MakeSwitchPair(t, getInitSwitchFunc(1))
+	defer s1.Stop() //nolint:errcheck
+	defer s2.Stop() //nolint:errcheck
+
+	normalReactor := s2.Reactor(reactorNameNormal).(*NormalReactor)
+	s1.Broadcast(0x01, []byte{1})      // the message for blocked reactor is first
+	time.Sleep(time.Millisecond * 200) // to make order among messages
+	s1.Broadcast(0x00, []byte{0})      // and then second message is for normal reactor
+
+	select {
+	case msg := <-normalReactor.msgChan:
+		assert.True(t, bytes.Equal(msg, []byte{0}))
+	case <-time.After(time.Second * 1):
+		assert.Fail(t, "blocked reactor is blocked")
+	}
+}
+
+func getInitSwitchFunc(bufSize int) func(int, *Switch, *config.P2PConfig) *Switch {
+	return func(i int, sw *Switch, config *config.P2PConfig) *Switch {
+		sw.SetAddrBook(&AddrBookMock{
+			Addrs:    make(map[string]struct{}),
+			OurAddrs: make(map[string]struct{})})
+
+		// Make two reactors of two channels each
+		sw.AddReactor(reactorNameNormal, NewNormalReactor([]*conn.ChannelDescriptor{
+			{ID: byte(0x00), Priority: 10},
+		}, config.RecvAsync, bufSize))
+		sw.AddReactor(reactorNameBlocked, NewBlockedReactor([]*conn.ChannelDescriptor{
+			{ID: byte(0x01), Priority: 10},
+		}, config.RecvAsync, bufSize))
+
+		return sw
+	}
+}
diff --git a/p2p/test_util.go b/p2p/test_util.go
index c709dfbb1..e190f234e 100644
--- a/p2p/test_util.go
+++ b/p2p/test_util.go
@@ -78,7 +78,7 @@ const TestHost = "localhost"
 // NOTE: panics if any switch fails to start.
 func MakeConnectedSwitches(cfg *config.P2PConfig,
 	n int,
-	initSwitch func(int, *Switch) *Switch,
+	initSwitch func(int, *Switch, *config.P2PConfig) *Switch,
 	connect func([]*Switch, int, int),
 ) []*Switch {
 	switches := make([]*Switch, n)
@@ -177,7 +177,7 @@ func MakeSwitch(
 	cfg *config.P2PConfig,
 	i int,
 	network, version string,
-	initSwitch func(int, *Switch) *Switch,
+	initSwitch func(int, *Switch, *config.P2PConfig) *Switch,
 	opts ...SwitchOption,
 ) *Switch {
 
@@ -199,7 +199,7 @@ func MakeSwitch(
 	}
 
 	// TODO: let the config be passed in?
-	sw := initSwitch(i, NewSwitch(cfg, t, opts...))
+	sw := initSwitch(i, NewSwitch(cfg, t, opts...), cfg) // receive buffer size is all 1000 in test
 	sw.SetLogger(log.TestingLogger().With("switch", i))
 	sw.SetNodeKey(&nodeKey)
 
diff --git a/privval/signer_listener_endpoint_test.go b/privval/signer_listener_endpoint_test.go
index dc3249511..9499d71ea 100644
--- a/privval/signer_listener_endpoint_test.go
+++ b/privval/signer_listener_endpoint_test.go
@@ -18,8 +18,8 @@ import (
 var (
 	testTimeoutAccept = defaultTimeoutAcceptSeconds * time.Second
 
-	testTimeoutReadWrite    = 100 * time.Millisecond
-	testTimeoutReadWrite2o3 = 60 * time.Millisecond // 2/3 of the other one
+	testTimeoutReadWrite    = 1000 * time.Millisecond // increase timeout for slow test env
+	testTimeoutReadWrite2o3 = 60 * time.Millisecond   // 2/3 of the other one
 )
 
 type dialerTestCase struct {
diff --git a/rpc/core/net_test.go b/rpc/core/net_test.go
index 56863a11f..d64ed94fd 100644
--- a/rpc/core/net_test.go
+++ b/rpc/core/net_test.go
@@ -14,7 +14,7 @@ import (
 
 func TestUnsafeDialSeeds(t *testing.T) {
 	sw := p2p.MakeSwitch(cfg.DefaultP2PConfig(), 1, "testing", "123.123.123",
-		func(n int, sw *p2p.Switch) *p2p.Switch { return sw })
+		func(n int, sw *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch { return sw })
 	err := sw.Start()
 	require.NoError(t, err)
 	t.Cleanup(func() {
@@ -48,7 +48,7 @@ func TestUnsafeDialSeeds(t *testing.T) {
 
 func TestUnsafeDialPeers(t *testing.T) {
 	sw := p2p.MakeSwitch(cfg.DefaultP2PConfig(), 1, "testing", "123.123.123",
-		func(n int, sw *p2p.Switch) *p2p.Switch { return sw })
+		func(n int, sw *p2p.Switch, config *cfg.P2PConfig) *p2p.Switch { return sw })
 	sw.SetAddrBook(&p2p.AddrBookMock{
 		Addrs:        make(map[string]struct{}),
 		OurAddrs:     make(map[string]struct{}),
diff --git a/statesync/reactor.go b/statesync/reactor.go
index 4da332469..3c82248c1 100644
--- a/statesync/reactor.go
+++ b/statesync/reactor.go
@@ -44,7 +44,7 @@ func NewReactor(conn proxy.AppConnSnapshot, connQuery proxy.AppConnQuery, tempDi
 		conn:      conn,
 		connQuery: connQuery,
 	}
-	r.BaseReactor = *p2p.NewBaseReactor("StateSync", r)
+	r.BaseReactor = *p2p.NewBaseReactor("StateSync", r, false, 0)
 	return r
 }
 
diff --git a/test/fuzz/p2p/pex/reactor_receive.go b/test/fuzz/p2p/pex/reactor_receive.go
index 6b2178559..040a2392d 100644
--- a/test/fuzz/p2p/pex/reactor_receive.go
+++ b/test/fuzz/p2p/pex/reactor_receive.go
@@ -18,8 +18,10 @@ var (
 )
 
 func init() {
+	cfg := config.DefaultP2PConfig()
+
 	addrB := pex.NewAddrBook("./testdata/addrbook1", false)
-	pexR := pex.NewReactor(addrB, &pex.ReactorConfig{SeedMode: false})
+	pexR := pex.NewReactor(addrB, cfg.RecvAsync, &pex.ReactorConfig{SeedMode: false, RecvBufSize: cfg.PexRecvBufSize})
 	if pexR == nil {
 		panic("NewReactor returned nil")
 	}
@@ -33,9 +35,10 @@ func Fuzz(data []byte) int {
 	// MakeSwitch uses log.TestingLogger which can't be executed in init()
 	cfg := config.DefaultP2PConfig()
 	cfg.PexReactor = true
-	sw := p2p.MakeSwitch(cfg, 0, "127.0.0.1", "123.123.123", func(i int, sw *p2p.Switch) *p2p.Switch {
-		return sw
-	})
+	sw := p2p.MakeSwitch(cfg, 0, "127.0.0.1", "123.123.123",
+		func(i int, sw *p2p.Switch, cfg *config.P2PConfig) *p2p.Switch {
+			return sw
+		})
 	pexR.SetSwitch(sw)
 
 	pexR.Receive(pex.PexChannel, peer, data)
diff --git a/test/maverick/consensus/reactor.go b/test/maverick/consensus/reactor.go
index e47845ed5..43c5a2bd9 100644
--- a/test/maverick/consensus/reactor.go
+++ b/test/maverick/consensus/reactor.go
@@ -55,13 +55,13 @@ type ReactorOption func(*Reactor)
 
 // NewReactor returns a new Reactor with the given
 // consensusState.
-func NewReactor(consensusState *State, waitSync bool, options ...ReactorOption) *Reactor {
+func NewReactor(consensusState *State, waitSync bool, async bool, recvBufSize int, options ...ReactorOption) *Reactor {
 	conR := &Reactor{
 		conS:     consensusState,
 		waitSync: waitSync,
 		Metrics:  tmcon.NopMetrics(),
 	}
-	conR.BaseReactor = *p2p.NewBaseReactor("Consensus", conR)
+	conR.BaseReactor = *p2p.NewBaseReactor("Consensus", conR, async, recvBufSize)
 
 	for _, option := range options {
 		option(conR)
diff --git a/test/maverick/node/node.go b/test/maverick/node/node.go
index a6f73ed65..9316fea7d 100644
--- a/test/maverick/node/node.go
+++ b/test/maverick/node/node.go
@@ -372,7 +372,7 @@ func createMempoolAndMempoolReactor(config *cfg.Config, proxyApp proxy.AppConns,
 		mempl.WithPreCheck(sm.TxPreCheck(state)),
 	)
 	mempoolLogger := logger.With("module", "mempool")
-	mempoolReactor := mempl.NewReactor(config.Mempool, mempool)
+	mempoolReactor := mempl.NewReactor(config.Mempool, config.P2P.RecvAsync, config.P2P.MempoolRecvBufSize, mempool)
 	mempoolReactor.SetLogger(mempoolLogger)
 
 	if config.Consensus.WaitForTxs() {
@@ -393,7 +393,7 @@ func createEvidenceReactor(config *cfg.Config, dbProvider DBProvider,
 	if err != nil {
 		return nil, nil, err
 	}
-	evidenceReactor := evidence.NewReactor(evidencePool)
+	evidenceReactor := evidence.NewReactor(evidencePool, config.P2P.RecvAsync, config.P2P.EvidenceRecvBufSize)
 	evidenceReactor.SetLogger(evidenceLogger)
 	return evidenceReactor, evidencePool, nil
 }
@@ -407,9 +407,11 @@ func createBlockchainReactor(config *cfg.Config,
 
 	switch config.FastSync.Version {
 	case "v0":
-		bcReactor = bcv0.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+		bcReactor = bcv0.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync,
+			config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 	case "v1":
-		bcReactor = bcv1.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+		bcReactor = bcv1.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync,
+			config.P2P.RecvAsync, config.P2P.BlockchainRecvBufSize)
 	case "v2":
 		bcReactor = bcv2.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
 	default:
@@ -447,7 +449,8 @@ func createConsensusReactor(config *cfg.Config,
 	if privValidator != nil {
 		consensusState.SetPrivValidator(privValidator)
 	}
-	consensusReactor := cs.NewReactor(consensusState, waitSync, cs.ReactorMetrics(csMetrics))
+	consensusReactor := cs.NewReactor(consensusState, waitSync, config.P2P.RecvAsync,
+		config.P2P.ConsensusRecvBufSize, cs.ReactorMetrics(csMetrics))
 	consensusReactor.SetLogger(consensusLogger)
 	// services which will be publishing and/or subscribing for messages (events)
 	// consensusReactor will set it on consensusState and blockExecutor
@@ -589,6 +592,7 @@ func createPEXReactorAndAddToSwitch(addrBook pex.AddrBook, config *cfg.Config,
 
 	// TODO persistent peers ? so we can have their DNS addrs saved
 	pexReactor := pex.NewReactor(addrBook,
+		config.P2P.RecvAsync,
 		&pex.ReactorConfig{
 			Seeds:    splitAndTrimEmpty(config.P2P.Seeds, ",", " "),
 			SeedMode: config.P2P.SeedMode,
@@ -599,6 +603,7 @@ func createPEXReactorAndAddToSwitch(addrBook pex.AddrBook, config *cfg.Config,
 			// https://github.com/tendermint/tendermint/issues/3523
 			SeedDisconnectWaitPeriod:     28 * time.Hour,
 			PersistentPeersMaxDialPeriod: config.P2P.PersistentPeersMaxDialPeriod,
+			RecvBufSize:                  config.P2P.PexRecvBufSize,
 		})
 	pexReactor.SetLogger(logger.With("module", "pex"))
 	sw.AddReactor("PEX", pexReactor)