diff --git a/Makefile b/Makefile
index d9dd6b473..2eb9d7449 100644
--- a/Makefile
+++ b/Makefile
@@ -57,7 +57,7 @@ endif
 INCLUDE=include
 MDEFINES=-DU2_OS_$(OS) -DU2_OS_ENDIAN_$(ENDIAN) -D U2_LIB=\"$(LIB)\" 
 
-CFLAGS= -O2 -g \
+CFLAGS= -O2 -g -msse3 -ffast-math \
 	-funsigned-char \
 	-I/usr/local/include \
 	-I/opt/local/include \
diff --git a/v/main.c b/v/main.c
index f40556c0e..c4dda2a84 100644
--- a/v/main.c
+++ b/v/main.c
@@ -18,6 +18,7 @@
 #include <termios.h>
 #include <term.h>
 #include <dirent.h>
+#include <pmmintrin.h>
 #include <xmmintrin.h>
 
 #define U2_GLOBAL
@@ -250,6 +251,7 @@ main(c3_i   argc,
   c3_w kno_w;
 
   _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
+  _MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
 
   //  Parse options.
   //