Have 4GB ram showing 2.25 but have other issue

[i3adi3oyMike]

Ok this is weird. I have read up on how xp 32bit cant utilize more then 4gb of ram. So here is my situation. This week I purchased 4-1GB sticks of pc5400 ddr2 ocz ram. I also bought a BFG Geforce 8800GT OC 512BM Pci-express card. Now where my problem is is that before I installed either of these things I had 2-1gb sticks and 2-512mb sticks of ram and it showed 3GB of ram for my system. I also had an ATI Radeon x800xt 256mb pci-express card.
So I installed the new video card and the ram and opened up My Computer and clicked on properties and at bottom it says 2.25GB of ram. Odd? Well I checked my bios and it shows 4GB of ram and I used CPU-z and it shows 4GB of ram. So I got to messing around after work today and kept changing out the configurations of ram anywhere from 3GB - 4GB and it would still show under properties that I had 2.25gb. So I decided just to see if it would make a difference and I took out my new video card and reinstalled my 256mb one, still having 4GB of ram in the computer and then the properties would show 3GB of ram.
Like I said I have read about the memory issue with 32bit xp but how would upgrading a video card remove 750MB of ram. I went from 256 to 512...this is very strange how my video card would do this. Any ideas?

 

[computeruler]

mabye xp is just saying you do but you still migh be able to use all of the ram anyways

 

[Cromewell]

The additional video RAM takes a bit but there's other addressing that is done as well. ~750MB seems like a bit much but it is what it is. You've removed or disabled the ATi driver right? I don't think it would stay around but I guess you never know.