I'm no expert, but actually, the OS running on the system, 32bit windows or 64bit, can affect how many Gb of your ram will work. OS's such as Windows XP Pro and 2003 Server allocate 4gb virtual memory address space equally. Limiting 2gb for user mode address space and 2gb kernel mode address space. This means If you have 4Gb ram installed, you will only b able to use 2gb, and the other 2gb being allocated to kernel mode processes. The 3Gb switch, a startup option (/3GB in boot.ini), can be used to reshuffle the allocation so that 3Gb is for the user and 1Gb is for kernel mode. 64bit OS's are now able to take advantage of 4GB of addressable memory. so basically if you wanna use over 3gb ram, get a 64bit processor and OS... i think..