only needs 3.3v but it uses a standard -12v to +12v ... in terms of actual consumption your looking at around 15mw
depending on what you wanna put in your comp will determine the power, but really in actualy terms of consumption it uses about as much as a USB device with independant power supply.
you can get 350watt PSUs now for a matter of $10, $30 if with a case. that should suit even the most demanding system, unless you happen to be running SCSI with over 4 Devices, or innumerable USB devices without independant power supplies.
heck, my P4-1.25ghz system with FX5600 Ultra and 4 IDE Devices runs happily on an old 230watt
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