Yesterday Apple released a new update for Max OS X 10.6.4 Snow Leopard, this update is said to improve overall performance and reliability for gamers.
From what we can see if you play Portal, Team Fortress 2 or Starcraft II you should notice improvements, prior to this update Starcraft 2 may quit unexpectedly or become unresponsive, whereas Portal and Team Fortress 3 would experience frame rate issues.
The update itself is 69.2MB in size and can be downloaded via software update, alternatively you can download it manually here, to install this update you must be running Mac OS X 10.6.4.
The frame rate issues are said to be a problem with a wide range of Macs produced in 2009-2010, these include mid-2010 MacBook Pros, mid 2010 MacBooks, early 2009 Mac Pros and a few of the iMac and Mac mini models.
It looks as if Apple, Valve, ATI and Nvidia worked together to produce this update, which makes you think it was a driver-related issue.
Have you installed this update? If so, have you noticed better gaming performance?