Yea, most of the time it's overkill. No 600-700W PSU will be able to handle high-end SLi/CF DX10, but a lot of people don't realize this. A simple 450W PSU can handle any single DX10 card, then you could add a Fortron X3 Booster 300W to support another card in SLi if needed. A Corsair HX520W is modular and can support almost all setups currently except Quad-SLi. For Quad-SLi a Corsair HX620W is recommended, or TT Toughpower 750W if you need more power for watercooling, RAID, OCing, or the like.