diff --git a/src/scr_conf.h b/src/scr_conf.h
index d84f729b..a83cf304 100644
--- a/src/scr_conf.h
+++ b/src/scr_conf.h
@@ -143,13 +143,12 @@
 
 /* buffer size to use for MPI send / recv operations */
 #ifndef SCR_MPI_BUF_SIZE
-/* #define SCR_MPI_BUF_SIZE (1*1024*1024) */
-#define SCR_MPI_BUF_SIZE (128*1024)  /* very strange that this lower number beats the upper one, but whatever ... */
+#define SCR_MPI_BUF_SIZE (1024*1024)
 #endif
 
 /* buffer size to use for file I/O operations */
 #ifndef SCR_FILE_BUF_SIZE
-#define SCR_FILE_BUF_SIZE (1024*1024)
+#define SCR_FILE_BUF_SIZE (1024*1024*32)
 #endif
 
 /* whether file metadata should also be copied */