Radeon HD 4850 driver issues in Win 7

I've been playing Assassin's Creed 2 on Sunday and intended to again today (I worked Saturday so I've been given Monday off in lieu in case anyone was wondering). However I'm having some pretty major issues. The game loads fine, but about 2 minutes in lines and weird angular blocks start flashing on the screen and then the game will freeze. I can alt-tab to windows at which point I see a message saying

"ATI display driver stopped responding and has recovered"

I can then alt-tab back into the game and play for another minute before the exact same thing happens again. I'm very puzzled since it worked well all the times I played it last week and I've not changed anything on my PC in that time. The card I'm using is an HD 4850 with which I have never previously had issues. I am running a dual screen setup at the moment (same as in my system thingy below my username, different monitors though and the graphics card now has a fan on it) and kept HW monitor open on the other screen to see if the card (or anything else) was overheating. Pretty confident it isn't since the max temp the card records is 64 C when under load. Regardless I tried leaving the computer for 2 hours (turned off) to cool down. Problem still present. I am at a loss to explain it or fix it so any help would be appreciated.

What you're describing could indicate a problem with the video card's memory - find a program that will let you test it. It may be worth uninstalling and reinstalling the drivers too, you never know.

Tried uninstalling the video driver and replacing with the latest one (just the driver, not the catalyst control software also). Same issue.

Any suggestions on a program for testing the video card memory? I guess it's possible that the card has broken, though I struggle to see how.

EDIT: used one I found here: http://www.technibble.com/repair-too...y-stress-test/

Indicates no errors in the memory. No closer to a solution and I'm out of ideas now.

Are there any updates available for the game itself? Have you added anything to your system lately? What PSU do you have, are you sure the card's getting enough power?

Not changed anything. At all. Not even allowed windows to do any updates since I've not been connected to the internet for the last few days. I'm certain the card has enough power. I've had it 2 years and not once had a problem even with more graphically demanding games. Overall power draw of the system at load was well below the PSU capacity when I last tested it.

Virus scanned with ESET. Found nothing. Updated drivers for GPU to no effect. I've found that games that previously ran fine all have the exact same issue now, artifacts appear, it freezes and the GPU driver crashes.

I can only conclude that the card is totally fubared. The odd thing is ever testing application that I run finds no problems at all which is very puzzling.

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Originally Posted by Emirzan

Not changed anything. At all. Not even allowed windows to do any updates since I've not been connected to the internet for the last few days. I'm certain the card has enough power. I've had it 2 years and not once had a problem even with more graphically demanding games. Overall power draw of the system at load was well below the PSU capacity when I last tested it.

Virus scanned with ESET. Found nothing. Updated drivers for GPU to no effect. I've found that games that previously ran fine all have the exact same issue now, artifacts appear, it freezes and the GPU driver crashes.

I can only conclude that the card is totally fubared. The odd thing is ever testing application that I run finds no problems at all which is very puzzling.

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I see you run it passive...it's just a guess, but the culprit might be related to overheating, have you checked how dusty the card is? also, I would double-check the temps.

That system thingy is out of date. I decided very quicky not to run it passive. It has a 120mm fan on the heatsink. Temps reported by HW monitor are approx (depending on ambient) 48C at rest and 55 to 63C on load (depending on how fast I let the fan spin). Heatsink appears clear.

Hmmm I suspect it's over heating and the stock heatsync that your running on the card is no longer performing as well as it should. Or your thermal compound has worn away. This happened to me on my 4850 when the temps hit over and above 80 degress and I'd get what you are.

So the solution was to get one of these

http://www.kustompcs.co.uk/acatalog/info_2888.html

Does the job so much better than any stock cooler and the card runs in at 37 degrees when idle and never goes above 45 when being hammered :)