diff --git a/setup.py b/setup.py
index af0abd6..19a2934 100755
--- a/setup.py
+++ b/setup.py
@@ -297,6 +297,7 @@ class CustomBuildExt(build_ext):
                 e.extra_compile_args.append("-Wno-unused-function") # quell some annoying warnings
                 e.extra_compile_args.append("-Wdeclaration-after-statement")
                 e.extra_compile_args.append("-Werror=declaration-after-statement")
+                e.extra_compile_args.append("-O3")
 
 
         # build in place, and in the build/ tree