I recently got a 5770 as an upgrade to my 9500gt and I have been having lots of trouble. When I run games, they usually crash after 5-10 min. I have had this happen with Crysis and Mass Effect, though I was able to get Oblivion running for 20 min with no crash.
When the games crash, they lock up the whole system and I have to hit my reset button or turn the PSU off. I don't get a BSOD, just a solid color (or black) with vertical lines on it. Sometimes I will get some flickering before the crash. A couple times I had the game crash to the desktop with the "driver
was not responding and has recovered" message.
I have tried to solve this by trying all the drivers
for this card (the ones on the cd, the recommended one on the AMD page, and the beta) while making sure to uninstall the old drivers + run driver sweeper in safe mode. I also have updated my chipset to the 7/21 release and my BIOS to version 501.
When I take the card out and replace it with my 9500 gt all the problems go away. I want to figure out if somehow something in my system is messing with this before I go ahead and RMA it only to find out that the card was not the problem. I don't have a minidump, but I have alot of kernel dumps from when the system froze, so I am going to attach it (I don't know if it works the same as a minidump). Thanks!