diff --git a/lib/terraspace/app.rb b/lib/terraspace/app.rb
index 46ea8ed4..e8b05838 100644
--- a/lib/terraspace/app.rb
+++ b/lib/terraspace/app.rb
@@ -43,6 +43,9 @@ def defaults
       config.build.default_pass_files = ["/files/"]
       config.build.pass_files = []
       config.build.dependency_words = []
+      # copy_modules = nil  # => Will show a warning and default to true
+      # copy_modules = true # => Will be default in next major version
+      config.build.copy_modules = nil # speed improvement
 
       config.bundle = ActiveSupport::OrderedOptions.new
       config.bundle.logger = ts_logger
diff --git a/lib/terraspace/builder.rb b/lib/terraspace/builder.rb
index 0de9d012..8051258e 100644
--- a/lib/terraspace/builder.rb
+++ b/lib/terraspace/builder.rb
@@ -69,7 +69,7 @@ def build_dir(type_dir)
       with_each_mod(type_dir) do |mod|
         is_root_module = mod.cache_dir == @mod.cache_dir
         next if is_root_module # handled by build_stacks
-        Compiler::Perform.new(mod).compile
+        Compiler::Perform.new(mod, type_dir: type_dir).compile
       end
     end
 
diff --git a/lib/terraspace/compiler/perform.rb b/lib/terraspace/compiler/perform.rb
index 2559b53a..b8f1d1f4 100644
--- a/lib/terraspace/compiler/perform.rb
+++ b/lib/terraspace/compiler/perform.rb
@@ -3,8 +3,9 @@ class Perform
     include CommandsConcern
     include Basename
 
-    def initialize(mod)
-      @mod = mod
+    def initialize(mod, options={})
+      # options for type_dir
+      @mod, @options = mod, options
     end
 
     def compile
@@ -60,7 +61,7 @@ def compile_config_file(file)
     end
 
     def compile_mod_file(src_path)
-      content = Strategy::Mod.new(@mod, src_path).run
+      content = Strategy::Mod.new(@mod, src_path, @options).run
       Writer.new(@mod, src_path: src_path).write(content)
     end
 
diff --git a/lib/terraspace/compiler/strategy/abstract_base.rb b/lib/terraspace/compiler/strategy/abstract_base.rb
index 85536ef1..22c38a66 100644
--- a/lib/terraspace/compiler/strategy/abstract_base.rb
+++ b/lib/terraspace/compiler/strategy/abstract_base.rb
@@ -1,7 +1,8 @@
 module Terraspace::Compiler::Strategy
   class AbstractBase
-    def initialize(mod, src_path)
-      @mod, @src_path = mod, src_path
+    def initialize(mod, src_path, options={})
+      # options for type_dir
+      @mod, @src_path, @options = mod, src_path, options
     end
   end
 end
diff --git a/lib/terraspace/compiler/strategy/mod.rb b/lib/terraspace/compiler/strategy/mod.rb
index 09ef1d24..a763180b 100644
--- a/lib/terraspace/compiler/strategy/mod.rb
+++ b/lib/terraspace/compiler/strategy/mod.rb
@@ -1,5 +1,7 @@
 module Terraspace::Compiler::Strategy
   class Mod < AbstractBase
+    include Terraspace::Util::Logging
+
     def run
       klass = strategy_class(@src_path)
       strategy = klass.new(@mod, @src_path) # IE: Terraspace::Compiler::Strategy::Mod::Rb.new
@@ -7,6 +9,9 @@ def run
     end
 
     def strategy_class(path)
+      # Significant speed improvement
+      return Mod::Pass if copy_modules?
+
       ext = File.extname(path).sub('.','')
       return Mod::Pass if ext.empty? # infinite loop without this
       return Mod::Pass if Terraspace.pass_file?(path) or !text_file?(path)
@@ -14,6 +19,39 @@ def strategy_class(path)
       "Terraspace::Compiler::Strategy::Mod::#{ext.camelize}".constantize rescue Mod::Pass
     end
 
+    @@copy_modules_warned = false
+    def copy_modules?
+      return false unless @options[:type_dir] == "modules"
+
+      copy_modules = Terraspace.config.build.copy_modules
+      if copy_modules.nil? && @@copy_modules_warned == false
+        logger.info "WARN: config.build.copy_modules is not set. Defaulting to true.".color(:yellow)
+        logger.info <<~EOL
+        The terraspace building behavior is to copy modules from
+        the app/modules folder to the .terraspace-cache for speed.
+        Most do not need app/modules to be compiled.
+        Other files like app/stacks and tfvars files are still compiled.
+        This is a change from previous versions of Terraspace, where
+        all files were compiled.
+
+        You can turn this warning off by setting:
+
+        .terraspace/config.rb
+
+            Terraspace.configure do |config|
+              config.build.copy_modules = true
+            end
+
+        In future Terraspace versions, the default will be true.
+        There will be no warning message, but it will still be configurable.
+        EOL
+        copy_modules = true
+        @@copy_modules_warned = true
+      end
+
+      copy_modules
+    end
+
   private
     def text_file?(filename)
       TextFile.new(filename).check