It sounds like bad memory on the video card. Can you call the vendor and say "give me a new one?"
THis stuff usually happens when you overclock a video card and you have the memory clock to high. Normally you just lower it a bit and you are fine. However, it this is on factory settings that may be the issue. If you can, you can try to lower the memory clock yourself and see if that helps. If it does, you know what the issue is.