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850w PSU not enough

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T

Thick8

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Apr 29, 2015
We received a kill-a-watts meter at work so I brought it home to see just how much power my computer was pulling from the wall. Just the PS cord, not the monitors or any peripherals. So I fired up Furmark on my pair of heavily overclocked 290s at 5760x1080 with 8xAA on. Then I fired up 8 threats of the heat generating Prime95 test on my 5Ghz FX-8350. HOLY CRAP, 940 Watts! Quick turn it off before it bursts into flames. Gotta give cudos to Corsair for a quality product.
So needless to say I'm in the market for a new PSU but am a little financially strapped with the flooding and all. I'm looking at the EVGA 220-P2-1200-X1. There's lots of positive reviews on it. Any personal experience here?
Thanks.
John
 
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Furmark is an unrealistic test and is known to kill GPU's.
Run Heaven instead.

Also, I highly doubt you hit 940A... more likely 940W.

Taking into account that you're probably around 85% efficient on your PSU, that's 799W that the PSU sees.
That said, 850W on the 12V rail is fine.
 
Unless you're overclocking the pee out of the chip and/or running the cpu and gpu's at 100% 24/7 you're fine with the Psu you have all depending on the quality of the unit you have.

Though, it is a bit shocking how much power these Fx 8xxx chips use when overclocked as well as the R9 290's.
 
I did say Amps didn't I. Oops, I meant Watts.
I'm looking at taking the system down about another 20-30c to gain some overclocking headroom and wanted to make sure the PSU was up to the challenge; so I maxed it out at the current overclock.
Atminside, I don't understand your math. If I'm drawing 930W at the wall, the PSU is rated at 850A and is 85% efficient; wouldn't I then be 131W over what the PSU should be able to safely handle?
Either way the PSU isn't rated for the power that the system is capable of consuming so I'm going to replace it.
 
You said amps again. :p

You take away from the reading at the wall. So if you saw 950W at the wall, multiply that by .85 (or your efficiency rating) to get the actual draw of the PSU. So 940 x .85= 799W actual draw.

Since you also did this in the absolute worst possibly scenario (using an unrealistic GPU test, and running P95 at the same time), I assure you that gaming loads will be over 100W less making that PSU just fine.

If you are still concerned, go ahead and grab the EVGA Supernova G2/P2 1000W. There is no need for 1.2KW... particularly if you are short on cash.

If I was you, I would re-test using Heaven and P95 to see where you are at. Then, play a game and see where you peak... I think you will be surprised to see how much of a difference it will make when one uses more realistic tests.

EDIT: One other thing... personal experiences on a power supply are pretty useless. It works, or it doesn't. Anecdotal experiences are not relevant here. Read reviews from Jonnyguru, [H], TPU, etc. That said, you picked a good one, but massive overkill.
 
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EarthDog said:
You said amps again. :p
Click to expand...

DAMN YOU André-Marie Ampère. You and your retched life.

OK, I'm having a thick (skull) moment. 930W is what the kill-a-watts says is going thru the cord to the PSU. So any way you slice it there is 930w being consumed by the computer. Are you saying that only 85% of that is going to power the system components and 15% is lost in heat and such.

EDIT: Now that I think of it that makes sense.
 
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Exactly. The WALL outlet is using 930w...your psu is actually putting out ~85% of that.

What corsair psu do you have specifically?
 
Thick8 said:
DAMN YOU André-Marie Ampère. You and your retched life.

OK, I'm having a thick (skull) moment.
Click to expand...
No pun intended? :D
Thick if you plan on pushing further then maybe it is a good idea to step up to a higher wattage Psu. A 1k unit should be fine unless you really plan on turning the screws on it.
 
EarthDog said:
Exactly. The WALL outlet is using 930w...your psu is actually putting out ~85% of that.

What corsair psu do you have specifically?
Click to expand...

CORSAIR Enthusiast Series TX850 V2 850W ATX12V v2.31/ EPS12V v2.92 80 PLUS BRONZE Certified Active PFC High Performance Power Supply

I've had it since March of 2012.
 
So it's 8 months later. I was playing FC3 in all its wonderful triple screen glory and there was a pop and my computer reset. Then i smelt something electrical in nature and investigated. HOLY CRAP this PS is HOT! SO I fired FC3 back up with the kill-o-watts inline and found that my machine is now pulling 1020 watts from the wall. That's not good. I think it's definitely time to get something with a little more oomph. So I've been learning a little about PS'. Let me know if I have this right.
Pulling 1020w at the wall. this PS is 81.5% efficient at 830w load (calculated from total draw at the wall) when it's new (it's not new). I've read that a PS is at it's most efficient when running at 80-90% rated load. So I should really be looking for a 1000w PS. That should be enough right?
 
I was checking this PSU at another site that ran extensive tests to the point of failure. they were able to max out at 1025w at the wall and measured it at 79.9% efficient. So I extrapolated there data to 81.5(ish)w at 830w.
Now my conundrum. I need to clean out my water loop. So there's going to be a complete tear-down. I also have an i7-4790 non-k. I can either buy a MB for $125 for the CPU or buy a 1000w PSU for $130. Less power to run the intel CPU but I'm grooving on many of the DX12 games that have, and are going to, come out. I've been reading that the new DX12 games are really taking advantage of the AMD instruction set and multi-core CPUs. graphs and charts all show the 2 CPUs neck to neck in performance when you take into consideration my OC. I just can't decide!
 
i7-4790 non-k should not use that much watts. Do you have a picture of your watts being used by your rig?
 
ATMINSIDE said:
Yes, a 1000W should be more than enough. Look at the EVGA G2.
Click to expand...

Funny but that's the one I have in my Amazon cart.
I think I'm going to stick with the 8350 CPU. I can always swap it out at a later date. I'm thinking about getting the Zen and Vega if they test well next year.
 
I wonder what went "pop" in your system.

Guessing it may have been a capacitor in the power supply perhaps.
 
Tech Tweaker said:
I wonder what went "pop" in your system.

Guessing it may have been a capacitor in the power supply perhaps.
Click to expand...

Not sure. It wasn't too loud. The fact that it fired back up leads me to think it was the over-current circuit breaker opening.
 
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