diff --git a/conf/intel/portage/env/nographite.amd64.conf b/conf/intel/portage/env/nographite.amd64.conf
index e9f0212..d0ce28d 100644
--- a/conf/intel/portage/env/nographite.amd64.conf
+++ b/conf/intel/portage/env/nographite.amd64.conf
@@ -4,5 +4,5 @@
 # Note that on GCC versions older than 4.5 using graphite is not
 # recommended, due to its instability.
 
-CFLAGS="-O2 -ftree-vectorize -march=x86_64 -pipe"
+CFLAGS="-O2 -ftree-vectorize -march=x86-64 -pipe"
 CXXFLAGS="${CFLAGS}"