Let, me solve this issue: sli doesnt necessarily double your amount of ram on your system, but both cards are working together. But just make sure your video card can run sli, not every one can, especially low-end ones. Like I dont even know if you can play a good game like call of duty or world in conflict at super-high quality even with two 512MB cards.
Someone's gonna get hurt.............IT AIN'T GONNA BE ME!!!!!!