diff --git a/dist-build/msys2-win32.sh b/dist-build/msys2-win32.sh
index d6e1ec36..bbe7b11a 100755
--- a/dist-build/msys2-win32.sh
+++ b/dist-build/msys2-win32.sh
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-export CFLAGS="-O3 -fomit-frame-pointer -m32 -march=pentium2 -mtune=nocona"
+export CFLAGS="-O3 -fomit-frame-pointer -m32 -march=pentium3 -mtune=westmere"
 export PREFIX="$(pwd)/libsodium-win32"
 
 make distclean > /dev/null
diff --git a/dist-build/msys2-win64.sh b/dist-build/msys2-win64.sh
index 3d3d3a77..43f0b697 100755
--- a/dist-build/msys2-win64.sh
+++ b/dist-build/msys2-win64.sh
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-export CFLAGS="-O3 -fomit-frame-pointer -m64 -mtune=nocona"
+export CFLAGS="-O3 -fomit-frame-pointer -m64 -mtune=westmere"
 export PREFIX="$(pwd)/libsodium-win64"
 
 make distclean > /dev/null