diff --git a/configure.in b/configure.in
index 1a2d7ede3bff..261b853c99d5 100644
--- a/configure.in
+++ b/configure.in
@@ -1966,7 +1966,7 @@ case "$target" in
         
         
     WARNINGS_AS_ERRORS='-WX'
-	MOZ_OPTIMIZE_FLAGS='-O1'
+    MOZ_OPTIMIZE_FLAGS='-Ox'
     AR_FLAGS='-NOLOGO -OUT:"$@"'
     ASM_SUFFIX=asm
     CFLAGS="$CFLAGS -W3 -Gy -Fd\$(COMPILE_PDBFILE)"