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The 700W PSU from my old/er computer...

Last response: in Graphics & Displays
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July 15, 2012 4:23:19 AM

Well, i'm buying two GTX670's, and i want to cut the payments, so I wanna use the old PSU of mine, which is 700W, 2 rails of 12V each 30Amps. Would i have problems with that? And if i'll ever want to overclock? (PSU's are horribly overpriced here, 200 dollars for a 850 one...)

EDIT: Ah, i forgot to mention, these two 670's are gigabyte factory overclocked.

More about : 700w psu computer

a b U Graphics card
July 15, 2012 4:28:49 AM

Does your PSU have 4 PCI-E power connectors? If not, I would not try SLI because the Molex connecters used for the PCI-E adapters does not provide the correct amperage for the 670.

If you do have the correct amount (4) PCI-E power connectors, you would be fine to SLI these cards as this review states.

http://www.guru3d.com/article/geforce-gtx-670-2-and-3wa...
a b U Graphics card
July 15, 2012 4:29:33 AM

How old is that PSU, What Brand ? a 700W PSU should be fine for 2 670 in SLI but it might be a really old one ( lower efficiency )..so post the brand and exactly how old is it.....
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a b U Graphics card
a b K Overclocking
July 15, 2012 4:32:34 AM

for OC'd 670,a quality 750w will do fine with 60+ amps on +12v rail(s).
a c 243 U Graphics card
a c 105 K Overclocking
July 15, 2012 4:40:29 AM

Brand and model? 700 watts is kind of an odd size. Most quality units are 750 watts. If it really had a 60 amp 12v rail it would deliver 720 watts on the 12v rail alone and would be labeled higher than 700 watts.

A quality 750w power supply is fine for a GTX 670 Sli setup even factoring in overclocking. By quality I mean Corsair, Seasonic, PC Power and Cooling, XFX, Silverstone, Enermax, OCZ or Antec. And a few specific models from other brands.
July 15, 2012 4:40:38 AM

It does have all the power connections needed, it has 80 plus bronze. And its 700 watt, not 750.
All the name says is Win+ 700Watt

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a c 243 U Graphics card
a c 105 K Overclocking
July 15, 2012 4:56:26 AM
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There are not alot of HEC power supplies here in the US or in Europe honestly so it's hard to find a real review of that model. I do know HEC makes all of Cougar's power supplies are they are mid range, not crap but not a high quality brand.

That model shows 648 watts on the combined 12v rails. Since volts x amps = watts we just divide 648/12 and get a true figure of 54 amps on the 12v rail. A system with a single GTX 670 needs a 30 amp 12v rail and adding a second card requires another 15 amps. Factor in some overclocking and you are looking at ~47-48 amps needed.

So assuming your power supply can actually supply the rated wattage and amps it should work. You are cutting it really close though. Personally I would feel better with a good ~62 amp 750w PSU. But it's up to you if you want to try it. In reality your cards will almost never pull full load. It all depends on the quality of your power supply.
July 15, 2012 4:58:27 AM

Best answer selected by snowcrush.
July 15, 2012 4:59:09 AM

anort3 said:
There are not alot of HEC power supplies here in the US or in Europe honestly so it's hard to find a real review of that model. I do know HEC makes all of Cougar's power supplies are they are mid range, not crap but not a high quality brand.

That model shows 648 watts on the combined 12v rails. Since volts x amps = watts we just divide 648/12 and get a true figure of 54 amps on the 12v rail. A system with a single GTX 670 needs a 30 amp 12v rail and adding a second card requires another 15 amps. Factor in some overclocking and you are looking at ~47-48 amps needed.

So assuming your power supply can actually supply the rated wattage and amps it should work. You are cutting it really close though. Personally I would feel better with a good ~62 amp 750w PSU. But it's up to you if you want to try it. In reality your cards will almost never pull full load. It all depends on the quality of your power supply.


Then i will go for it, whats the worst that can happen if there's no enough power, right? Its just trying to save 200 dollars :p 
So thanks ^_^
a c 243 U Graphics card
a c 105 K Overclocking
July 15, 2012 5:02:11 AM

Actually the worst that could happen is your power supply could blow up and take you cards, motherboard and CPU with it. Personally I would not try it with a power supply of unknown quality. Sorry I can't give you a better answer.
July 15, 2012 5:23:15 AM

Well ive been with this power supply for a year or so and its very high quality as far as im concerned... It costed fuckloads :p 
a c 271 U Graphics card
a b K Overclocking
July 15, 2012 11:48:35 AM

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