PC hardware forum: Calculating power Supply needed

My short version.

20 Watts per drive.
100 Watts for the CPU
40 Watts for the mainboard.
40 Watts for the usual video card
100 Watts for the firebreathing video card.

Add it up and then double it so it lasts for years.
Bob

if it's not a gaming video card, just get a 400w power supply.

I've looked this over several times and this is generally difficult to do. The best I'd determined was that if you purchased a $3,000.00 or less PC then go 500 watts, over $3000.00 then 1000 watts. Seams I was right. My calculations from this site recommended 447 watts for my system.

http://extreme.outervision.com/PSUEngine

I would suggest the originator of this post look for a PS that is at least 80% efficient or better. Also the heavier the PS the better. Yep, heavier by weight. This means the PS has more windings and is of better quality. Also, if your running a SLI video card you will need an SLI Power Supply.

With up grades I have a $1,200.00 PC. 500 watts would run it well with a little wiggle room. The three thousand dollar mark was for high end multiple (two or more, maybe four) hard drives, more then likely RAID. Two or more Video cards, 4-8 GB RAM, quad processor and water cooling. Certainly this type of PC would need more power. Most PCs are pretty "run of the will" till you pass the 3 grand mark. A system builder might create a $2,000.00 PC that would need a 1000 watt PS but they'd need to be a really shroud shopper. There out there on the net somewhere but the audience here is more mainstream. My comments reflect the audience we deal with here, not the PC gamer elite.

Thanks for this but I'm finding that not only must I consider Watts but the Amperes on the "rails."

Some power supplies have plenty of Watts but fall short on the Amperes needed for these graphic cards because the +12V rail is not one but many.
Bob

20 Watts per drive.
100 Watts for the CPU
40 Watts for the mainboard.
40 Watts for the usual video card
100 Watts for the firebreathing video card.