Hi there, hope someone can help me out! I'm not really a gamer but I thought I'd purchase Doom 3 to play now and then and to show off my lovely new 23" ACD and my new Mac Pro Anyway when I'm in the game and moving around I get lines running horizontally through the screen? I can only describe it as sort of a tv interference? I've tried the game on all the various settings etc all to no avail. I've just downloaded the Quake 4 demo and it's the same problem with that as well Apart from the strange lines the games look wonderful. I've nothing nearby like speakers etc that might be causing interference and I've checked my that my software updates are all up to date. Do you think it's a compatibility issue with the 8800 card? Thanks in advance for any help. Mac Pro 10.5.2, 2 x 2.8 Quad Core, 4GB, 8800GT.