You're browsing the GameFAQs Message Boards as a guest. Sign Up for free (or Log In if you already have an account) to be able to post messages, change how messages are displayed, and view media in posts.
To the OP, that's because a Windows OS on Mac hardware runs better than a mac OS on mac hardware...I have actually run benchmarks and it's hilarious that windows takes better advantage of the mac hardware than OSX does :)
My 2008 macbook with 4 gigs of memory can run this on ultra/high (lowered shadows and shaders) just fine. The only problem I noticed is that there seems to be a memory leak. I have to restart the game after 3-4 hours or it gets unplayable.
On my windows partition I can run it on full ultra without the memory leak. Blizzard just needs to optimize better.