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Can I run a Hd radeon 5770?

Last response: in Graphics & Displays
April 23, 2010 5:27:14 AM

Hi, I was reading around the forums to find the amperage that the 5770 requires and it seems that a 30A - 40A +12v is required to run this card. But I was wondering if any one has been able to run it w/o meeting the amperage requirements, because my OCZ ModxStream 600W only has 25A on each of its +12v rails.

Here's my setup: AMD PII X4 955 @ 3.7
4GB DDR3 Corsair memory (2x2gb)
2 DVD Drives
1 Hard Drive
3 case fans, 1 cathode light

Thanks in advance.

More about : run radeon 5770

April 23, 2010 5:34:04 AM

if your motherboard is attached to one rail, the one pci-e power connector to the other it will work. That way it can draw from both rails
April 23, 2010 10:46:53 AM

Its the combined 12v rating that you're looking for, and I would suspect that with 2x25A max rails your combined 12v output will be about 40-45A. A 5770 is only spec'ed for about 110w peak draw. 110/12 = 9.2A - and they never use this much in the real world anyway. The 30-40A is a total system rating and basically covers the manufacturer for you putting one in a overclocked quad core system with about 80 HDDs and a million fans, or one with a cheap PSU.
Bottom line is OCZs are fairly good and you can run a 5770 easily with that PSU - you could crossfire 2 of them even.
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April 23, 2010 2:42:14 PM

That's a very similar PSU to what I'm using, and I run a 5770 perfectly fine.
April 23, 2010 5:14:46 PM

You shouldn't have a problem with your PSU being able to supply this card.

Best solution

April 23, 2010 10:25:19 PM

This was a misinterpretation of ATI's suggested PSU sizes for an entire system that keeps getting repeated. The math just doesn't work.

40 amps x 12 volts = 480 watts.

450 Watt or greater power supply with one 75W 6-pin PCI Express® power connectors recommended (600 Watt and two 6-pin connectors for ATI CrossFireX™ technology in dual mode)

So how could ATI say your entire system could run conservatively on 450 watts when the GFX card was pulling 480 ???

You can do the math yourself here:

the 5770 works out to a peak 119 watts or just under 10 amps.
April 23, 2010 10:44:26 PM

You cannot draw more than 25 AMPS from a 25 AMP rail. That's why they call it a 25 AMP rail. There is much mis-info around on PSUs.
April 28, 2010 5:56:15 PM

Best answer selected by darkslash_323.