I've had this BFG 8800GT 512 OC for about a little over a year now I guess. It came factory clocked at 625/1550(600/1500 stock). Never seemed to have any problems with it until the other day when I blew the huge amount of dust that had accumulated in my system out. I have an air compressor that puts out a lot of pressure, so I made sure to protect the fans of everything to avoid breaking them...it's happened in the past.
Fast forward to the other day when I install Mass Effect. Lost video signal on my monitor every 10-15 minutes, working perfectly up until that point. Dawn of Discovery followed suit, freezing every 10-15 minutes with a neon artifacting effect on the entire screen. The only game that seemed unaffected was Team Fortress 2.
I installed RivaTuner and monitored the video card temps while playing ME or DoD. My card was hitting 125C and then shutting down, every time. I remembered that it was OC'd so I brought it back down to stock speeds, and it fixed Mass Effect. It still runs at about 100C but it's stable. DoD continued freezing until I lowered the video ram from 900Mhz(which should be its stock speed) to 800Mhz.
So now I've got it stable, albeit with slightly underclocked RAM and stock GPU/shader speeds. But there's the terrible heat issue. My case airflow isn't the culprit here, I have an Antec P180 with two 120mm intake fans on the front and a rear and top 120mm exhaust fan. Taking off the side of my case and venting it with a large box fan actually resulted in higher temps.
Is it worth getting an aftermarket GPU heatsink/fan for this card or should it hold for a few more months until I upgrade to a GTX2XX?
Did you happen to buy it online? Since you said "receipt" I doubt it, but if you did could get the invoice from whatever site you bought it from probably. Good luck if you didn't.
Does that sound abnormally low?
Did you happen to pay with a credit or debit card or use a rewardzone (their shoppers club) card? If so, they can look up your receipt and reprint it for you. It's possible that they may even be able to do a manufacturer's warranty exchange out for the item at the store.