I can't decide to go sli or not with 2 8800 gtx's. The main problem is definitly the money. By the time I get the cards there should be price drops so that won't be toooo bad but my psu is only 600 watts so I would then need either a new psu or a thermaltake dedicated gpu psu, also I need a new mobo to run sli which would add 150ish to the comp, then I am iffy if my case can even fit 1 gtx so I might even need a new case. Is it worth the performance boost? I'm guessing not but it might be. Also same question for sli ultra's. Will the extra money put into the ultra's make the performance boost worth it? Thanks