Mid 2009 Apple MacBook Pro:
* CPU: Intel Core 2 Duo @ 2.53 GHz
* RAM: 4GB DDR3 @ 1067 MT/s
* GPU: Nvidia GeForce 9400M 256MB, 197.16 WHQL
* HDD: Intel X25-G2 SSD 80GB
* Screen: 1440x900
* Sound: Built-in sound
* OS X: Version 10.6.3 with latest updates
* Windows: Version 7 64-bit with latest updates
Hackintosh:
* CPU: Intel Core i7-975 Extreme Edition @ 3.33 GHz
* Motherboard: Gigabyte X58A-UD7
* RAM: 18GB Kingston DDR3 @ 1079 MT/s
* GPU: ATI Radeon HD 4890 1GB, Catalyst 10.4
* HDD: Intel X25-G1 SSD 80GB
* Screen: 2560x1600
* Sound: Built-in sound
* OS X: Version 10.6.3 with latest updates
* Windows: Version 7 64-bit with latest updates
[Image: http://cache.gawkerassets.com/assets/images/9/2010/05/500x_500x_benchmarx.jpg]
Steam for Mac Benchmarks: Windows Is Much Faster - Steam - Gizmodo
There you go
a large difference