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650w Psu enough for 2 gtx 770 sc

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  • Gtx
  • EVGA
  • Bullet
  • Components
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December 10, 2013 12:02:42 AM

Well, the gtx 580 refurb I had ordered from newegg came DOA. So i bit the bullet and bought a EVGA gtx 770sc, with ACX cooling. My question is, will my power supply be enough to handle two of them, should I decide to go SLI in the future. My system specs are as follows:
i5 2500k, oc'd to 4.2
8g gskill 1600 speed ram
crucial m500 ssd, 120g
1tb seagate barracuda, 64mb cache
MSI z77a g45 mobo
EVGA Supernova 650 Nex 650g PSU.
I also have 6 case fans, and a corsair h60 cpu cooler.

More about : 650w psu gtx 770

December 10, 2013 12:07:03 AM

Not really. If you want to run 2 then you would have to upgrade to a 750W PSU.
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December 10, 2013 1:25:45 AM

Your graphics cards and CPU both use the 12 Volts supplied by the PSU. When you overclock the CPU that's less power available for the graphics cards.

Power supplies vary in how much power they supply on the 12V rails as well.

A single GTX770 can draw as much as 250W though it's usually closer to 200W when gaming but you must use the worst-case scenario.

Thus TWO of them draw 500W, plus whatever the CPU requires. That's just on the 12V rails again, not the entire PSU.

An overclocked 2500K uses around 130W I believe (106W fully stressed stock). I'm guessing a bit here.

So that's say 630W needed for the 12V rail, again a worst case scenario and I'm spit-balling. The AMPERAGE is thus 630/12 or 52.5Amps.

So a 750Watt PSU would work in a real-world scenario but when stressed you may even need an 850Watt PSU with the proper 12-Volt amperage.

(don't flame me if I made a mistake).

Nope, looks like I'm dead on: http://www.guru3d.com/articles_pages/geforce_gtx_770_sl...

"GeForce GTX 770 2x SLI - On your average system the cards require you to have a 700~800 Watt power supply unit as minimum."
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December 10, 2013 1:35:16 AM

photonboy said:
Your graphics cards and CPU both use the 12 Volts supplied by the PSU. When you overclock the CPU that's less power available for the graphics cards.

Power supplies vary in how much power they supply on the 12V rails as well.

A single GTX770 can draw as much as 250W though it's usually closer to 200W when gaming but you must use the worst-case scenario.

Thus TWO of them draw 500W, plus whatever the CPU requires. That's just on the 12V rails again, not the entire PSU.

An overclocked 2500K uses around 130W I believe (106W fully stressed stock). I'm guessing a bit here.

So that's say 630W needed for the 12V rail, again a worst case scenario and I'm spit-balling. The AMPERAGE is thus 630/12 or 52.5Amps.

So a 750Watt PSU would work in a real-world scenario but when stressed you may even need an 850Watt PSU with the proper 12-Volt amperage.

(don't flame me if I made a mistake).

Nope, looks like I'm dead on: http://www.guru3d.com/articles_pages/geforce_gtx_770_sl...

"GeForce GTX 770 2x SLI - On your average system the cards require you to have a 700~800 Watt power supply unit as minimum."


Thanks for your reply. The psu calc on newegg said 823 watts, which youve just confirmed with an article from guru3d.

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December 10, 2013 1:36:12 AM

photonboy said:
Your graphics cards and CPU both use the 12 Volts supplied by the PSU. When you overclock the CPU that's less power available for the graphics cards.

Power supplies vary in how much power they supply on the 12V rails as well.

A single GTX770 can draw as much as 250W though it's usually closer to 200W when gaming but you must use the worst-case scenario.

Thus TWO of them draw 500W, plus whatever the CPU requires. That's just on the 12V rails again, not the entire PSU.

An overclocked 2500K uses around 130W I believe (106W fully stressed stock). I'm guessing a bit here.

So that's say 630W needed for the 12V rail, again a worst case scenario and I'm spit-balling. The AMPERAGE is thus 630/12 or 52.5Amps.

So a 750Watt PSU would work in a real-world scenario but when stressed you may even need an 850Watt PSU with the proper 12-Volt amperage.

(don't flame me if I made a mistake).

Nope, looks like I'm dead on: http://www.guru3d.com/articles_pages/geforce_gtx_770_sl...

"GeForce GTX 770 2x SLI - On your average system the cards require you to have a 700~800 Watt power supply unit as minimum."


Thanks for your reply. The psu calc on newegg said 823 watts, which youve just confirmed with an article from guru3d.

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