So I have an overclocked Sapphire 1gb Vapor-x 4870. Right now it is sitting at a 790mhz GPU Clock, and a 1100mhz memory clock.
When doing normal computing, I never I see a problem, but when I pop in a game, I get a visual pop, where block dots pop in and out all over the place, then, if I move an object in the game really fast, the whole game becomes un-calibrated and shuts off. Again, this is only during games. The weird part of this is that my OC'd 4870 passes ati's catalyst control center stress test (test custom clocks). Another possible problem is that the 'current values' of the ati overdrive section still show my gpu clock at 500mhz, but my memory at 1100mhz, even though on the values above, where you can actually control it, it is displaying it at 790. I don't know why its failing to display my current settings in the 'current values' section, or why even though it passes the stress test provided by ati overdrive, it still fails in games, no matter what the visual settings.
Another thing is that no matter what, my FPS is always at or above 60. Especially with my current settings, I would expect my FPS to drop to around 40!
I've exactly the same card and similar problems when I try a little more OC (colored popups). Actually I have my GPU working at 800Mhz and memory at 1000Mhz and no problems. Trying the "autotune" procedure, it stops GPU at 835Mhz and memory at 1060, but during game (tried Batman Arkham Asylum) sometimes the game freezes for a while, then I heard the GPU fan at maximum speed and the game works again, tehn the fan stops and in a few seconds the game freezes again. I noticed that in this case If I manually enable the fan, and set it to a speed of 50-65% , things get really really better and the game works fine. Weird behaviour anyway ...
The bad thing is that once I've tried OC and experienced problems, resetting GPU and memory to normal values doesn't fix the "popups"...I've to restart the system (the first time I was afraid my card was fu**d up!) to get things normal.
About FPS stuck at 60 it's the same for me, I read it's something about vsync (but I've it off by deafult) and even setting my display refresh at 75hz or disabling vsync in the game, fps remains 60. Being honest, it's enough to play very very well (with almost perfect visual experience and without fan spinnig noisily), but it's curious....
I think I'll try to contact ATI support for explanations...
Those are artifacts, and are signs of too high of a GPU clock. In my experience with my 4870, artifacts pre-crash are from too high of GPU, and solid lock-ups or VPU recoveries occured when my ram was clocked too high.
I don't trust CCC stress test and auto tune settings. Trial and error has lead me to my 4870 clocks, stable in every game I play, and this process has taught which games I can turn it up a bit further on.
I am able to clock my vram higher, but have experienced almost no performance increase over 1025mhz (benches and games) since I started running 3.55ghz on my CPU. I keep it at this speed for a bit of piece of mind and longevity, heh, though I have had it stable at 1100mhz. For example I only get about 30-50 points more in 3dMark06 when running 1100mhz over 1025. Sure it pushed me over 16k, but not worth it for me for the extra aging for such a small difference.
but not worth it for me for the extra aging for such a small difference.
You're perfectly right Jofa, (and i think that risking your card for 3dmark score is not a good policy ), I'm just worried about the fact that after the "artifacts" if i reset GPU and VRAM clock values I need a system restart to make it right....it sounds weird!