Apple's seriously sexy new iMac has been hit with random freezes that seemingly lock new owners of the machine out of whatever they're doing.

Apple has apparently blamed the problem on the ATI Radeon HD graphics card inside the iMac, but a fix has yet to be issued by the company.

Some users on the Apple Discussion Forum are reported as saying that the iMac doesn't crash completely - you can still hear music playing in iTunes for example. But the user interface no longer responds to mouse clicks or keyboard commands.

The 24-inch iMac we currently have on test doesn't appear to have this problem.

We're hoping to receive an official comment from Apple and ATI on this issue later today.