On my Mac, I'm building Aquaria. After I built it and moved the files over to the old Aquaria application bundle (replacing the original executable and scripts), when I play the game and shoot in energy form, it gets jittery. But I haven't noticed this slow-down on the version that came with my Humble Indie Bundle. The compiler I'm using is llvm-gcc 4.2, but it was present also when I used Clang. I am building a 64-bit binary because the 32-bit build has popping sounds instead of audio.