I built this computer almost a year and a half ago so during August I decided to start overclocking my components.
I started with the CPU, I have a i7 930 overclocked to 3.4 ghz since August and everything has been fine. I have a 750 Watt PSU from Corsair.
Just a few days ago I thought since my computer has been stable without any crashes, I decided to overclock my GPU. I have 2 GTS 250s in SLI from MSI that are already factory overclocked, but I decided to use the program that came with it to finally overclock it some more. I upped the shader clock by 40 MHz, and the memory clock by 50 MHz. I ran it like this for a day playing lots of Starcraft 2 and thought everything was ok at max settings with a good 45 FPS at 1920 x 1080.
Then yesterday I decided to try playing Witcher 2 with the so called SLI fix with Nvidia Inspector that makes both GPUs work at full capacity (the game itself doesn't support SLI and only 1 card is used). The temps rocketed from 40C to 70C in minutes so I blasted the fans at 90% to cool the GPUs to a constant 50C. However this is where all the problems started to pop out. After I stopped playing Witcher 2 and went back to playing Starcraft 2, I started to get minor artifacts and screen tearing. Then I herd some loud cracks coming from inside the PC case. It sounded like a branch breaking off. This never happened so I thought it was weird and freaked out. I closed SC2 and restarted the computer, and I still had the same problems. So I reset the GPUs to factory settings and the artifacts and tearing were gone from SC2. Then I let my computer rest for the remainder of the day.
But today my GPU setup has crashed 4 times. Each time it happens a bunch of artifacts pop up, my screen freezes for 2 seconds, then my computer just stops outputting an image. I can still hear the music being played from iTunes, but just no video output. This has happened without any games being played, and during games being played. In fact I can't even seem to replicate the crashes. They just happen out of the blue. I already reset the clock to factory settings...I don't know why the GPU still keeps crashing.
I need to know if this means my GPU is failing or not, or if there's some other inherent problem I'm not aware of like if I overloaded the PSU when I overclocked the GPU. Is there some diagnostic program I can run to test this stuff?
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The game doesn't utilize SLI properly and lowers the frame rate quite a bit. The weird thing is some people don't have the problem, but some do. I think some people suggested that it's a problem with certain retail versions or something, but I don't understand how that works.
Before I used this fix I checked the GPU usage on Afterburner and most of the load was carried by 1 card. It wasn't until I tried this fix that the GPU loads were evenly distributed.
Try the new witcher 2, 1.4 patch with latest nvidia drivers, sli should work great now
(here my system gets 99% gpu utilization)
Another silly stuff to do is reinstall drivers.
and run gpu-z to make sure ur clocks indeed is default.