memory - 64-bit Windows 7 can only use 3.25GB of RAM instead of 4GB?

Possible Duplicate:
How to enable 4GB in my Windows 7 64 bit?

My Windows 7 is 64-bit, and I thought that means it can use the full 4GB of RAM installed on the computer.

But I just saw this on my computer's properties: (So only 3.25GB is usable??)

Answer

This is usually down to either memory being shared against a graphics card or a motherboard limitation that prevents 4GB of memory being accessible.