Aluminum iMac Update

Apple has released an update to fix the video freezing problem which some people experienced on their 20" or 24" Aluminum iMac.
This update is not offered on all of these machines. It is only available for those machines that need it.
Note: For it to appear, it is necessary to have installed the iMac Software Update 1.2.1 in Tiger or the iMac Software Update 1.3 in Leopard.
It is a firmware update for the video card. Once the software is installed, it is necessary to run the "iMac Graphics Firmware Update" which is found in the Utilities folder.