RAM/Video RAM question

[aikoe]

System:

Core 2 duo E7400 2.8ghz
4gb ddr2 800 RAM
XFX Geforce GTS 250 512mb
sucky intel motherboard (http://www.newegg.com/Product/Product.aspx?Item=N82E16813121389)
Windows 7 64x


I have a problem(may not even be a problem) that I cant figure out. My windows system information says Installed Memory: 4.00 GB (3.00 GB usable). In DXDIAG under display it says the aprox total memory: 1775 MB. Shouldn't my video card only have 512mb memory? Is my video card using my systems memory? How would I go about allowing my pc to use all its ram, or would it be best to leave it as is?

(i've already googled this and tried the common fixes for unusable ram. my motherboard doesnt have a memory remaping option, maximum memory box in msconfig is unchecked)

 

[Maziar]

Do you have 2x2GB RAMs ? if so then try each stick simultaneously and check if they are shown as 2GB.