I was planning on getting a ATI Radeon X850XT Platinum Edition video card for my new gaming rig but it doesnt support SLI, my question is, what is SLI? What does that do for me? (I dont know all that much about computer hardware...LOL). I was also gonna get the ASUS A8N-SLI Deluxe Socket 939 NVIDIA nForce4 SLI ATX AMD Motherboard. Thanks for any help.