I recently built an AMD 64 system for a friend, I found a really nice motherboard that came with a dual gpu nVidia Geforce 6600 GT card. Its a Gigabyte GA-K8nXP-SLI, with a GV-3D1. Its better to show then explain what the problem is. As you can see in the image I have attached there is an obvious problem with Unreal Tournament 2004. This only seems to appear during 3d applications, especially DX9 complaint games. 2d games (i.e. worms world party) shows artefacts onscreen... same with the dxdiag tests. I have tried all the usual remedies to sort the problem out. Driver updates (done correctly, original drivers uninstalled, deleted then replaced with latest ones), BIOS updates, reformatted, tried various Service packs only been able to test on DX9.0c. Whats really annoying is that it was working fine for about a month, then this fault occured for no apparent reason. I'm currently in the process of seeking tech support from the gigabyte website, then failing that it goes back. Thats something I do not really want to do. If anyone can help that would be greatly appreciated.