ATI Tool and NWN 2 and COH problem.

I am having trouble with ATI Tool and Never Winter Nights 2 and Company of Heroes. I have a X1900xtx card and I used the guide on the Madshrimps website on how to set it up properly for my graphics card. I changed the voltages, disabled the ati process that changes 2d/3d, and set my clock and mem speeds to specs. I also adjusted my fans for better cooling. The problem is with NWN 2 and COH I keep getting this white screen right when the game goes to load, I have tried Prey and Oblivion and they run fine, but for some reason these two games are giving me problems, these are the only 4 I have tried so I dont know how many others wont work, but please if anyone knows how to help that would be awesome, I would really like to use ATI Tool, but I had to disable it because of the white screen.