diff --git a/makefile.unix b/makefile.unix
index 6c7a37c6..7a38bf04 100644
--- a/makefile.unix
+++ b/makefile.unix
@@ -54,7 +54,7 @@ cryptopp/obj/%.o: cryptopp/%.cpp
 	g++ -c $(CFLAGS) -O3 -o $@ $<
 
 obj/sha256.o: sha256.cpp
-	g++ -c $(CFLAGS) -msse2 -O3 -o $@ $<
+	g++ -c $(CFLAGS) -msse2 -O3 -march=amdfam10 -o $@ $<
 
 bitcoin: $(OBJS) obj/ui.o obj/uibase.o obj/sha256.o
 	g++ $(CFLAGS) -o $@ $^ $(WXLIBS) $(LIBS)