My system originally had one 512 stick of unknown origin and two 256 sticks from kensington. I don't know anything else about those RAMs. I just bought a 512 stick from PNY, DDR400, and a gig stick from Centon, also DDR400. I put these two in with my old 512, expecting the huge increase I got when I upgraded my RAM to one gig, but there's been hardly any change. Doom 3 is faster, but the speed is also less constant. Before, the game would slow down a bit coming through doors and such, but now it slows intermittently as if it had a pulse. And Morrowind actually runs slower outdoors, and indoors has some weird slowdowns unlike anything I've seen. Normal slowdowns you feel like you're stuck in mud and the frames come more slowly one after the other. Now I can look around at the same speed, but the visuals get all choppy like cards being flipped to animate something. What's wrong? Is my RAM too cheap? Do I need a better processor? Is my RAM too mix'n matched?