If we're to believe the pre-release hype, Fermi will be the fastest single-GPU videocard on the planet when it ships, leapfrogging ahead of ATI's HD 5870. But all that power is going to come at a cost, including a beefy 600W power supply, according to reports from CeBIT .
We've often seen inflated power supply requirements, as GPU vendors have to take into account lower quality units and how the all-important +12V rail distributes amps. But in this case, it looks like Nvidia's talking about a 600W PSU "with a minimum 12V current rating fo 42A," which would indicate a higher quality unit.
By comparison, AMD's dual-GPU 5970 requires a 650W power supply and is rated at 294W TDP. In single GPU territory, AMD's HD 5870 requires a 500W PSU, or 100W less than Fermi.