Quote Originally Posted by Dr Unne
I can't find any info on whether the 450W PSU Samuraid mentions is enough to run an X2 3800 or 4400 and the Geforce 6800.
The 450W supply is definitely enough to run even an X2 4800+ and a 6800 Ultra and a few HDDs if you wanted.
I'm running a Pentium D830 (which uses far more power than an X2), 3 HDDs, a 6800GT, and a few optical drives off the 450W supply and it maintains stable operation even under 100% load on both CPU cores.

You can calculate you expected power usage here, which is roughly accurate:
http://www.jscustompcs.com/power_supply/

EDIT:
Good power comparison charts:
http://www.tomshardware.com/2006/01/...lt/page19.html