updated 04:05 pm EST, Mon December 21, 2009
Problems linked to ATI cards
Apple has released a new graphics firmware update, directed at 27-inch iMacs. The patch fixes flickering and corruption problems, which Apple attributes to the Radeon HD 4670 and 4850 video cards the computers may be equipped with. Downloaders must have Mac OS X 10.6.2, and avoid any sort of power interruption during the update process.
The glitches may be one of the reasons behind recent shipping delays, which pushed delivery times to over two weeks. People have also mentioned cracked screens; NPD analyst Stephen Baker suggests that the issue is simply one of high sales, rather than any technical difficulties. Apple has not provided any official explanation for the situation.