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Sufficent Power Supply?

Last response: in Components
May 7, 2011 12:30:58 AM

Here's a list of the relevant parts in my PC:

SAPPHIRE 100282-3SR Radeon HD 5850 (Cypress Pro) 1...
ASRock 870 EXTREME3 AM3 AMD 870 SATA 6Gb/s USB 3.0...
SAMSUNG Spinpoint F4 HD204UI 2TB 5400 RPM 32MB Cac...
AMD Phenom II X4 955 Black Edition Deneb 3.2GHz 4 ...
LITE-ON Black 24X DVD+R 8X DVD+RW 8X DVD+R DL 24X ...
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 ...
COOLER MASTER Hyper 212 Plus RR-B10-212P-G1 "Heatp...

Now, here's my power supply:

Rosewill Libertas Series LIB-650 650W Continuous @...

In hindsight, probably not the best unit to have purchased. So, with the Sapphire 5850 Xtreme at $149, I was thinking of purchasing another 5850 in crossfire. The only catch being that I only have two pci-e slots. I was thinking of getting a pair of splitters and using that to power the cards since rail can carry 50A. However, I'd really prefer not to toast anything. Does anyone have experience with this?

For reference, I'm running the processor on 1.425v at 3.8ghz.

More about : sufficent power supply

a b ) Power supply
May 7, 2011 12:50:58 AM

I think you would not see good results using a splitter and in my opinion you psu is not enough to hold out.
A second card requires you to add another 170 Watts. You need a 650+ Watt power supply unit if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 55~60 Amps available on the +12 volts rails.
a c 274 ) Power supply
May 7, 2011 3:01:09 AM

That's not going to happen with a splitter one 5850 draws 30A.
You need a quality 650W with 4xPCIE connectors and 60+ Amps on the +12V.
The Antec TPN 650W has all the above and is priced under $100.
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a c 144 ) Power supply
May 7, 2011 3:54:38 PM

That 30 amp figure is recommended for a complete "typical" system.

A pair of 5850's draws less than 25 amps. Figure 10 amps for the CPU and that's 400 watts. The rest of the system will not pull more than 100 - 120 watts. A 650 watt PSU will provide sufficient power. I, however, would use a 750 watt PSU.

Davcon, 60 amps X 12 volts = 720 watts.

Having said that, the Antec would be a better choice, but Homestar already owns the Rosewill.

Keep in mind that Rosewill is a lot like CoolerMaster. They keep trying to build good PSU's but they are not quite there yet.
a c 274 ) Power supply
May 7, 2011 5:16:32 PM

Thanks for the explaination jsc, your input is appreciated.