Well, I just recently placed more memory and a 8800gts on a motherboard that had integrated graphics. The thing is, I suspect that some of my memory is still going towards the integrated graphics in the motherboard. Is there any way I can stop that?
You need to go into the BIOS when you boot-up your computer. That is usually by pressing the Delete key when you start computer up (which I tap until it shows it going to Bios').
If you are unfamilar with changing stuff in your BIOS', the go to the motherboard manufacture page for the mobo you have and download the Online PDF Manual. Read it on how to set the bios and where to Disable the Onboard Graphic.