Yes it is true, however the minimum power requirement would be a 400w or greater since you want +12v@22A combined minimum for your rig and recommend a 450w or better which would work out to +12v@26A combined.
yap i know.
it just that i'm buying tomorrow this rig for a friend, & didn't know if i need to buy a special PSU. with the cheap case i get a 500W 4+4 pin PSU.
@ 85% efficiancy i get 435W truepower. i wanted to know if it's enugh... & if the calculation is right, than it is.
for the +12v calc, I usually choose cpu/gpu/hdd/dvd/2 fans (or devices that load up the +12v only, memory / system board loads up the +3.3v / +5v rails). So...
eXtreme PSU calc"]System Type: Single Processor
Motherboard: Regular - Desktop
CPU: Intel Core 2 Duo E6420 2130 MHz Conroe
CPU Utilization (TDP): 90% TDP
Video Card: NVIDIA GeForce 8800 GTS 320MB
Video Type: Single Card
SATA HDD: 1 HDD
DVD-ROM Drive: 1 Drive
Regular: 1 Fan 80mm; 1 Fan 120mm;
Keyboard and mouse: Yes
System Load: 100 %
Recommended Wattage: 253 Watts
But, don't forget to subtract the "no load" system board wattage of 38w
253-38=215w or 17.9A at most on the +12v rails combined.
Pad that at the 80% mark, you want minimum +email@example.comA on your PSU.
The truepower 430w should handle that w/o an issue if you can get it cheap. Go w/ a 500+ unit if you have the budget, they usually handle +12v@35A or so - then upgrades and longevity are part of the consideration.