Hm, I've got an HP dx5150 which has an inbred ATI card and the ATI RS480 chipset, and have been trying to use a PCIe 7300 GS but have been running into what sounds like this hard hang in both SLED10 and openSUSE 10.2 (and 10.1 before that). For further info, I'm running dual head with 1600x1200 and 1280x1024. I've tried the 9746 drivers (and just about every revision prior) and still get this problem, though inconsistently. It usually happens faster if I'm doing 3D stuff, but sometimes it doesn't matter.
In SLED10 (using Xgl/Compiz) it can take a couple days before the problem occurs, and I can't seem to accelerate it with load. Sometimes it even happens overnight with just about nothing running (blank screen saver), including if I'm not running Xgl/Compiz, btw (though takes longer). In openSUSE 10.2 (Xorg/Compiz), however, I can usually hang it up just poking around the desktop within 10 to 20 minutes.
Any thoughts or suggestions? Is there anyway to identify the cause of the hang? With the 9746 drivers, what specific fix might have helped others and how can I test it? Did they fix it for everyone else but me?
Thanks for any help... Cheers!