Ok well, I've tried all of your suggestions for doom 3, none of them are working for me so far =(. The ram is running in dual channel 2t is disabled, fast writes is disabled, all AA and AF is disables and i've screwed with every option in doom.
An ironic thing...I think the power supply in MY pc fried the toher night, or at least something did. I got home from school yesterday and my pc didnt start, so I ordered a new PSU..but my old one would boot my brothers POS 766 celeron.....oh well, start with the cheapest component first i guess.