The 9800GTX+
Minimum of a 450 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 24 Amp Amps.)
Minimum 550 Watt for SLI mode system.
(Minimum recommended power supply with +12 Volt current rating of 30 Amp Amps.)
The GTX260
525W PCI Express-compliant system power supply with a combined 12V current rating of 38A or more*
Two 6-pin PCI Express supplementary power connectors -or- One 6-pin PCI Express and two 4-pin peripheral supplementary power connectors
NOTE: For the power requirements of multiple GeForce GTX 260-based graphics cards in an NVIDIA SLI configuration
*Minimum system power requirement based on a PC configured with an Intel Core 2 Extreme QX9650 processor