I have been using my 4870 with games like Crysis, Far cry 2, Eve, The sims 3 for over a year now, and it has given me hardly any trouble.
However a few weeks back i installed 'Warhammer 40000: dawn of war', a relatively old game, it kept on crashing after 15 minutes of play, i tried a small underclock and it did the trick, no more crashes, weird uh?
This also happened with 'Empire Earth', i did the same thing and it stoped crashing.
Now, just a few days ago i purchased Battlefield:BC2, and the game crashes if my 4870 is run at stock, and usally right on the menu, before i can even start a game. I tried underclocking again, and found i have to do a huge underclock for it to run stable. (around 550mhz core 650mhz ram) which slows the card down alot.
The crash can be a blank screen, blocks all over the screen or grey lines with the audio of the game droping out soon after, I have no choice but to force restart the computer at that point.
I know my card is not overheating, i have run a 100% load stress test on it for 30mins+ using ATItool and the temp maxed out at 75 with no probs.
Why is this happening? it seems so strange to have to do this.
Asus PQ5 Deluxe
Corsair 1066 2GB RAM
Corsair Hx520 PSU
WD Caviar black 640
Windows 7 64bit
HUGE thanks for any input or to anyone who has an idea of what could be wrong, i can't find anyone else with this problem online!
Try running furmark if you haven't already (about the toughest GPU stress program out), then if that is fine run prime95 and furmark together. If it crashes when doing both it could point to the PSU being on the way out as it will give you 100% CPU and GFX load at the same time, which is more akin to (probably significantly higher than) your gaming load. If your system handles that then you can probably rule out the PSU and will have to start looking at other components.