What size power supply do I need?

Grok13

Honorable
May 27, 2012
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I am building a workstation for 3D modeling and FEA. These are the components I will be using but I am unsure of the wattage required for the PSU. I would also like to leave room for future improvements such as crossfire. Thank You

ASUS Sabertooth X79 mobo
I7-3820
AMD FirePro V5900 - maybe 2 as an upgrade
120GB SSD
750GB 7200RPM


 
Solution
For a system using two AMD FirePro V5900 graphics cards AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 26 Amps or greater.
Since you have some rather expensive components, and you'll be doing some heavy computing, I suggest you buy a good, expensive PSU. Preferably from Corsair, since they make the best PSU's, quality and power-wise. I recommend a AX 850, or if you really want the best, go for the AX 1200
 

A quality 600W will run his system easily.
 
An AMD FirePro V5900 is equivalent to a Radeon HD 7750.

Both cards use less than 75 Watts and don't have any PCI Express Supplementary Power Connectors.

The power supply requirements will be similar.

An 850 Watt or 1200 Watt power supply is a complete waste of money.
 


That is true, but if you compare the prices of a AX 650 and a AX 850, there is just a 40€ price difference. And since he already has some quite expensive hardware, I don't think that he wants to get cheap with the PSU.

If he gets a second graphics card, 600 watts might not be enough. Or it might, but just and just.
 

His whole entire system including the 2 graphics cards won't even draw more than 400W under load.