I feel your pain AND your frustration. Try replacing your power supply (PSU) with one that has at least 18 amps on the +12v line and 550 watts total power. Reason being is that about 2 months ago, I ordered a nvidia 6800 GS. My psu at the time met the minimum requirements for the card; 18 amps +12v, and 400 watts. However, I also had 2 UV LED fans in my case, a 120mm and an 80mm, along with 2gb ram and some led's on the front of the case. My card did EXACTLY what you're describing: pixelation everywhere, and all the other horrors to boot. I returned the first card only to find that the second card was doing the same thing, but worse. After installing multiple drivers and about 30 minutes on the phone with eVGA, they told me that my card requires
a psu with 18 amps on the +12v line, and a minimum of 400 watts. They also told me that they reccomend
20 amps/550W. I ordered a psu that has 18 amps on the +12v line and was 550W. Installed it and no more problems, it works perfectly.
Now, I'm not saying that this is it for certain, and would feel bad if you ran out and spent money on a power supply and it didn't fix it. I am saying that I had the exact problems that you had, and that it was because my power supply wasn't good enough to handle it. Not to mention that it was a cheap psu too, as it only cost me $20. The one that I replaced it with was a name brand and was $79.
Hope this helps!
War produces veterans, wounded both physically and mentally. They have sacrificed for us.....and it is now our job to help these veterans, as they have already helped us in ways we will never know, in ways that we cannot fathom, and in ways that we take granted every day.