has he got the money lying around to buy another 680, if he has then do it, if not then don't. Buy a slightly cheaper 680 (they are all the same board underneath apart from the really pricey ones) and put the extra money into the PSU. The PSU is the foundation. Its £30 for a reason. If its the fractal tesla then you won't have a problem, but you won't get one of those for £30.