Guppy! ..... good advice from
Grozdan "Think of it like this and save yourself some grief" Add together the combined price of those two sexy Windforce GTX 570s............and go out and buy a single,Nuclear powered, kick-ass card......1.5 or even 2Gb of dedicated video memory.......you'll probably find the real world difference to be marginal at worst over 2, 460/470 cards in SLI
and Half the worry of two cards in piggy-back mode........if there high performance, or SOC, or even OC..........one's gunna get cooked that close together..........
unless you can get at-least one PCI-E slot between them 250mm fans look inexpressive......but can't fill a plastic bag.........hard to explain but there good at suppling air if there's little or no pressure in the case .... a good set of exhaust fans are paramount to make this combination work ..... high end video cards need a good supply of cool air.....lots of it.......getting rid of that air is more important in keeping the cards from turning the inside of your case into an oven within minutes.
Temp related BSODs are a proverbial PITA......(Pain in the Ass)....
Aussie Allan