Question about PSU Calcs

[drunkles]

I've checked out a couple different PSU calculators, including of course www.extreme.outervision.com. What i'm a little confused about is whether the amounts given are the total overall wattage, or just the for the 12V rails? Seems too high to be just the 12V to me but some friends and i were talking about it and now we've confused ourselves :lol:

 

[Doughbuy]

Should be total system power. But the fact of the matter is that most components draw power off the 12V rails, the mobo, CPU, GPU's, HDD's, etc... so it would be safe to say total 12V power is equivalent also.

 

[SciFiMan]

You don't have to be that precise about it, because the quality of PSU's are so varied. You could have a weak 350 or a strong 350 for instance. In general the heavier the PSU the better quality it is. A quality 400-500 will cover all general systems. People running multiple video cards should start at 650 as a minimum. An 850 is pretty much more than anyone needs and leaves room for future growth. I wouldn't bother trying to calculate it unless you're trying to get by with the very least amount of power you need today. But I would rather just buy a PSU once for a system and never have to worry about having enough juice as I add things down the road.

 

[jaguarskx]

The calculators determines the power for all the rails. But they tend to overestimate the amount of power your PC will use. But it's better to an overpowered PSU than an underpowered PSU. Most components draws power from the 12v rails. The few exceptions are the motherboard, various PCI cards, RAM, and floppy drives. Hard drives and optical drives draws power from both 12v rail and 5v rail.