diff --git a/Compiler-Notes.md b/Compiler-Notes.md
index 2026a43..b84a3ef 100644
--- a/Compiler-Notes.md
+++ b/Compiler-Notes.md
@@ -1,5 +1,6 @@
 Random notes on compiler results in terms of runtime speed and library size
 
-## Mapnik [2.1.x branch](https://github.com/mapnik/mapnik/commit/c6fd387469633ee7055aee606abb6f5d3d936a29) with clang++ `3.3 (trunk 177655)` on OS X 10.7
+#### Mapnik [2.1.x branch](https://github.com/mapnik/mapnik/commit/c6fd387469633ee7055aee606abb6f5d3d936a29) with clang++ `3.3 (trunk 177655)` on OS X 10.7
 - -Os: libmapnik.dylib is `16.2` MB and tests run in `3.9s`
 - -O2: libmapnik.dylib is `12.8` MB and tests run in `3.7s`
+- -O3: libmapnik.dylib is `12.5` MB and tests run in `3.7s`