Quote Originally Posted by MrMojoZ View Post
Don't think about it then, look it up. 32bit OSes can address 4gigs total. All ram in the computer is included in that.

^^^ This man is correct.

Before I switched over to a 64-bit OS, I was running 4gb ram with 2x 8800gts 640mb cards and Windows would only show 2.75gb of system memory.

This is due to the limitations ALL 32-bit operating systems have in that they max out at 4gb address space. And because physical address space is used to address more than just RAM, it also has to address ALL of the memory contained on system devices such as graphics cards, network adapters, audio cards, system ROM, etc. In addition, many devices have have their registers addressed, further reducing how much ram a 32 bit OS can utilize.