Apple has released iMac Software Update 1.3, which "provides important issue fixes and is recommended for the aluminum 20-inch and 24-inch iMac models with 2.0, 2.4, or 2.8 GHz processors." (Mid-2007 iMacs).
The update apparently fixes a previously reported issue where users experience frequent system freezes/crashes from their Mid-2007 (Aluminum) iMacs. Some users reported that their iMacs are now crashing from something as simple as mousing over the Dock. The consensus among users appears to be that some iMacs' graphics cards are problematic, and the iMac 1.1 software update (released in September), which contains updated graphics drivers, made the problem worse in some cases. This means that not all machines are affected by this issue -- only those that appear to harbor the flawed graphics cards.
If you've noticed any other specific bug fixes after the update, please let us know.
Update Shortly after this release, Apple silently removed from their Web site the Tiger version of the iMac Software Update 1.3, along with all references to it (so that the URL listed in our article broke). It has now been replaced, apparently, with iMac Software Update 1.2.1 for Tiger, which is said to be directed at "20-inch and 24-inch aluminum iMac computers with 2.0, 2.4, or 2.8 GHz processors running Mac OS X Tiger", and purportedly "improves the performance and reliability of graphics-intensive games and applications and fixes an issue that some customers encountered when installing Mac OS X Leopard after applying iMac Software Update 1.2". It's a little hard to see how this statement can be coherent: how can a Tiger update fix a problem that now exists on Leopard?
That aluminum iMacs are indeed continuing to encounter graphics problems, such as freezes, is beautifully documented at this web site.
Anyway, please do let us know how you get on with this latest attempt to fix these iMac graphics problems.Resources