XP does not support 4 gigs of RAM!!!!!!!!!! Don't make the mistake of buying 4 gigs and planning on using it. It did before SP2 (I think), but you will never get an updated version of XP to detect 4 gigs. Apparently a small number of people have gotten it to work, but if you google you will find loads of people that are pissed about it. I have 4 gigs, and XP will only detect 3 no matter what I do. From the link I gave above the OP should have seen that XP supports 4GB RAM, but splits it evenly between kernel and apps (?); ie 2G each. You can tweak it (registry?) to force 1G kernel, 3G apps. So, yes, the best you will "see" is 3G. Anyone know what the kernel actually means? I realise (assume) it's the kernel of the OS, and so I assume the means the OS has 1G to play with, now matter how little it uses. @Dean Roddey, Eeek, that's some crazy RAM requirements! :-) BR JN