7900GT issues

Hi there!

Im writing this (first post by the way) because my 7900GT is behaving strangely.

For a while i have been getting these weird artifacts in every game i play, they aren't common though and doesnt influence gameplay. By the way, my mobo is an Asus A8N32-SLI Deluxe. They have been appearing roughly since i upgraded to the latest drivers (169.21), but it was around that time that i also tried some overclocking on the card with rivatuner, but i dont think i strained it too much, and i didnt screw around with any bios setting.

Anyway, Ive been running this program called Video Card Stability Test, and i have since disabled and uninstalled rivatuner.

When i ran the stability test for the first time it ran for about 20 secs and them it told me it had found an artifact, failing the test. I thought it was the driver so i installed the previous one (163.75). But still it made no difference. Im not sure how much i can trust this program, one of the reasons im posting here.

While running these tests i monitored the temperature of the gpu with everest and the highest it got was 81ºC. I dont think thats too much for a gpu, and my case is well ventilated.

Then i ran a benchmark in the same program, dont if any of you is familiar with it but it consists of a spinning Earth, near the end the image gets like this:


And then the image gets even worse.

Interesting thing is that i went to the bios and increased northbridge vcore, and now the stability test runs for a little over a minute without presenting me with the error.

I wonder if this is a hardware problem. Do any of you have any ideas?

Thanks, and sorry for the long text.