I've got a Mac Pro 5,1 with 32GB RAM, and a Radeon HD 5770 GPU with 1GB VRAM. I'm running 10.6.8. I had two displays on this card for awhile, but a few months ago, I started getting random pixels in random windows. They come in random colors, and are mostly solid, but not completely (and they differ in shading randomly as well). If I restart the Mac, the problem goes away for a day or two, but then comes back. Consistently. Recently, it stopped supporting two displays, so I had to disconnect one. I'm looking at a couple of things. One is that I'm not hearing a fan in my Mac Pro, and wondering if things are overheating. This room is so noisy, I'm not 100% sure. Are the fans typically quiet? Second, I'm looking to buy a new GPU, and wondering what the best recommendation is for my system. Thanks!