Which do you think will run windows better? I have done benchmarks tests in 3DMark2003 With 1.5GB at 200 MHz I get 5600 With 1.0GB at 400 MHz I get 5900 So it's a 300Mark difference. My MAIN question is: What does the MHz do specifically? I realize it's the 'speed' of the RAM, but what does the RAM speed specifically correlate to? I thought maybe the more MHz the RAM runs at the more data it can transfer a second? No? Thanks In Advance Note: I have an AMD Athlon 64 And the reason I need to figure this out is because i cant run all the ram at 400mhz. It's PC3200 but when i set it to 2:1(400mhz) in bios, my computer stalls right when the windows screen comes up. I've narrowed it down to RAM and the RAM's Speeds.