not true you can set it up to use 4gb, Example, it can use 1gb for windows and 3gb for programs but won't use all 4gb all at once together. It is a server mod. What I'm saying is the memory is designated and not fluid as needed like it is in vista, only the first 3 gb really are in windows xp. You can install 4gb but unmodded xp will only really uses 3gb fluidly and server modded you must designate what it uses over 3gb. You use a method called the 3 MB switch by changing the boot file you allowcate 1 gb to windows and 3 gb to programs. This really doesn't make a difference unless you use your computer as a server.