[babuskov]

I have never seen such huge difference. I'm playing and making games and most of them run 10% faster on Windows at most, and this is due to graphics driver.

However, there is one thing that is a major difference: the system timer. Windows sleep() call has a granularity of 10ms, while OSX one has 1ms. So, if you (or your game library) is using sleep to return unspent CPU time to OS, it's easy to write the code that would run fast on one OS and very slow on the other.

Most developers treat OSX version as a checkbox on their "required features list" and only care whether the game works or not when porting. They do not want to spend time looking at the intricacies of OSX and just tell you that it's graphics driver's fault.

I develop games on Linux and OSX and later port to Windows before releasing (because that's where the players are), so I have to write specific code for Windows to make sure it runs faster. For example, my latest Steam game was really lagging and slow on Windows until I figured out the timer problem I wrote about above.

Other developers do it the other way around, and OSX performance isn't top priority.