If you have 1GB video card it helps a lot moving it above the actual RAM address
space. There are other devices that would also otherwise map onto the 4GB space.
4GB RAM + 512MB video + misc hardware would yield me about 3.25GB under x32 where I
get fill 4.0GB on x64.
On 4/29/2010 7:32 PM, Bobby Heid wrote:
It maps into the address space of whatever the 64-bit address space is (8
terabytes or something like that). When you have a 32-bit OS, the address
space is only 4GB, the system maps in the hardware memory (BIOS, graphics
card RAM, etc.) space from the top of the address space down. That is why
you get between about 3-3.5GB of actual RAM when you have 4GB RAM on a
32-bit system. I know I'm not explaining this well, so take a look here:
http://www.codinghorror.com/blog/2007/03/dude-wheres-my-4-gigabytes-of-ram.h
tml
and
http://support.microsoft.com/kb/929605
