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Making sure I have the right Power Supply

Tags:
  • Gtx
  • Power Supplies
  • Geforce
  • Graphics
Last response: in Graphics & Displays
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July 6, 2014 11:59:22 PM

Current Rig Setup:

GC - GeForce GTX 780 Ti
Mobo - ASUS MAXIMUS VII HERO LGA 1150 Intel Z97
CPU - i7-4770K 1150
Heatsink - Cooler Master Hyper 212 EVO

Corsair 650D Tower, running 32GB SSD for OS and WD Green 1TB for internal hard drive for everything else, standard Blu-Ray optical drive, 24" ASUS VG248QE/144hz/1ms for monitor, Corsair Vengeance K70 gaming keyboard, Razer Naga mouse, and 4 4GB G. Skill Ripjaws (7-7-7-18)

I'm looking into the Corsair AXi 860w for my power supply, 80 plus platinum certified. I've used many a PSU calculator and so far they have all produced extremely different results (444w-1100w difference), so I did some of my own calculations and decided that 860w would be the way to go. However, just to double check, would this be enough or even too much? Also, if I were to get a 2nd 780 ti to go dual cards, would it still be enough if it already is for a single?

No OC planned.

Edit: Obviously shooting for 90% PSU usage efficiency. It seems like the answers have already taken that into account.

More about : making power supply

a b ) Power supply
July 7, 2014 12:21:56 AM

For single card, this is more than enough (which is a good thing, you won't overload the PSU). The PSU is top quality, so great choice there. For 2 cards in SLI, however, I'd go with 1000W; this PSU may be enough, but would be constantly under heavy load.
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July 7, 2014 12:29:23 AM

780ti TDP = 250W
i7-4770K =84W
There rest is probably not more than 50W.
250+84+50 = 384 / 0,8 (PSU efficiency) = 480

So that 444w was probably raw value based on the configuration... which is fair.
From my point of view 500W is absolute minimum and you have to be sure that almost all of it is delivered from 12V lines.
If you hence do do some overclocking I'd put some more horsepower tho... but anything above 650W is rather a waste of cash imo.

Edit: I didn't reed it completely...
For another card like this you need to add 312W... so yeah if you are thinking about another card like this you would need minimum ~800W.
So the answer is yes it will be enough but 0% OC... if you think about that 20% more is a must... which is like herrwizo said ~1kW
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a c 94 ) Power supply
July 7, 2014 12:43:38 AM

You said no OCing and even adding another 250 to the figure Ra_V_en came up with, that's still only ~650W. That Platinum 860W can do that with ease. I'd go a bit lower if you are staying with one card, but it's fine for two.
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July 7, 2014 1:39:29 AM

Thanks for all of your help and input, as it got me to research even more.

My current rig setup should be using about 580w, no OC, under a roughly full load (current games at max/ultra graphics). 90% of the 760w AXi = 684w, giving me about 100w of breathing room, and allowing me to OC some if I feel the need.
If I were to go 2 card SLI, then the usage would be roughly 750w, no OC. 90% of the 860w AXi = 774w, so that would be about right on the money. However OCing would be an issue by that point.

Note that for the "full-load usage" I rounded up by a few 10's here and there so the actual usage may be a bit lower, but I always play it safe. Better to have a little too much than too little. And I'm not saying that I won't OC, it's just that for now my limited understanding of the subject and building computers has me.. hesitant to do so.

But I'm feeling very enlightened and very excited to begin building my first computer. Again, thanks for the very helpful input. My lack of knowledge of exactly how you guys got the numbers caused me to keep searching for the answer, therefor causing me to answer my own questions with the assistance of people who know what they are doing. Teaching men to fish on this site :) 
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a c 94 ) Power supply
July 7, 2014 1:42:59 AM

Quote:
My current rig setup should be using about 580w


How do you figure? You said in the OP that was your current setup. And it was estimated that the usage was just under 400W. Why do you think it's nearly 200w more then that?
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July 7, 2014 1:51:59 AM

http://www.tomshardware.com/reviews/core-i7-4770k-haswe... - Average consumption roughly 100w

http://www.guru3d.com/articles_pages/gtx_780_ti_sli_gef... - 372w full stress, 262w subjective = roughly 300-350w under normal stress

Mobo average 50w, usually no more than 75w.

blu-ray drive, ssd, hard drive roughly 10w each = 30w

I know that equals 505w-555w and contradicts the previous 580w stated, but as I said last time I rounded up more, this time I rounded up less and is more accurate.
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a c 94 ) Power supply
July 7, 2014 2:02:16 AM

Double check those numbers. That 372W full stress number is for the SYSTEM, not just the card. That was the entire system, and it only used 372W. That's really close to the "guess" that Raven gave of 384W. Their GPU measurement was 262W. So two cards in SLI would be just over 500W. Again, you'll be fine.

Motherboards aren't anywhere near 50W btw. All they have on them now is the SB/MCH. The NB and with intel now the VRMs are on the CPU. Modern MBs are probably around 10-12W max. I haven't seen a measurement of MBs recently.
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July 7, 2014 2:11:18 AM

I'll make the investment in the Corsair AX760i due to quality components and features to allow myself room for 2 card SLI and possible OC. Again, thanks for all the help.
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