Here's the deal. I have been running w2k for the longest with the below system specs. Well I put a 2600+ to test it on a build I was doing. I couldn't raise the multiplier so I figured it was my Dec 2002 bios I was running. So I tried the latest June Bios and then my netcard wouldn't work. So I was going to install Xp Pro anyway so I figured any issue would be fixed with the new Xp install. Well still didn't work and found out that you have to manually input the mac address on the new BIOS. Well after that I noticed I couldn't do next to nothing on overclocking, the system would hang at the settings W2k would run no problem. I mean I could only hit 200fsb x 9.5 @ 1.95v where the W2k would run 206fsb x 9.5 @ 1.9. So I tried a ton of older BIOS , seems like the older BIOS works the best for overclocking. Does Windows XP Pro reduce some of my overclocking ability? Can't understand why I have to jack my voltage up now , is it the BIOS change or the OS change you think>?