i've got (Kingston 1GB 800Mhz RAM)x4. and my WinXP & Vista uses only 3.2GB of it. and dunno where is other 867KB on XP. on vista it looks like it's sharint it with VGA. but its still like my XP.
How can i use FULL of it?
Yep When I had my 4gb in Vista shared a lovely 768mb or something memory with my GPU, not that it matters really as it doesnt ever use it unless it needs too, which isn't a bad thing if you run out of memory space on the GPU.