Which would give me better performance, sli 8800 gts 640mb or one 4850? I already have one 8800 so the prices are similar for these cards. I do have an sli mobo, so wouldn't be using two 4850s and don't want to lay down the cash for a gtx 260 or 4870. Please no fanboy flaming, keep it civil and please give reasons for your opinions as well as links if you have them. Thanks!!!