Power Supply for Crossfire

J

Jeengy

n00b
Joined
Feb 3, 2015
Messages
2
Hey fellas, I have been digging around for a while and finally decided to make an account after lurking for a long time.

I wanted some input from those of you with extensive crossfire (or sli) setup experience. I plan on getting 2 of the new amd cards (hopefully) in the summer and if I were to assume they draw a little more than the 290x, would 1000w be overkill?

I have a custom loop with a d5 pump and a sandy bridge 3820 at 5ghz. I would like to overclock the new video cards on top of my cpu, which may be upgraded (skylake pls) but still heavily overclocked.

TL;DR - Is 1000w overkill for watercooled, heavily overclocked cpu and 2 way overclocked xfire 290x? (380x but let's use 290x for now)
 
Last edited:
According to this article at [H] HERE, a system with a pair of 290x's overclocked in Crossfire is using 776W under load.

I'd say it really depends on what % load you want for your power supply. For instance, if you grabbed an 860W Seasonic power supply, you would be running it at about 90% load. If you picked up a 1000W unit, you would be running it at about 78% load. I have seen it stated many times that the "sweet spot" for % load is between 65% and 85% load.

If there is any sense to the "65%-85%" rule that is out there, I think a 1000W power supply would make sense for your situation.
 
Cool, thanks for the response. I know the new evga g2 psu's are well regarded even by johnny guru, and the 1300w is 10 dollars more than the 1000w. I have found mixxed feeling about the efficiency sweet spot you spoke of, and I know I don't want to pay top dollar to jump from gold to platinum.

I guess what I was hoping for out of asking you guys for help was an absolute huge overclock on 290x's and what the power draw is like on a day to day basis along with an oc'd cpu.
 
I now have a Corsair AX1500i with the USB data link. Just running the desktop it says I pull 110 or so from the wall and just loading up BL2-The Pre Sequel or Ryse: Son of Rome right now it’s around 600W. There may be more demanding games and for reference, if I run FurMark and Prime95 it can hit 1000w. I don’t think any game will do that but I wonder how many crashes on the 1000w Seasonic were because I was too close to the supplies ceiling.

The Corsair is very expensive but I didn’t like the Seasonic being so loud while gaming. I was disappointed after water cooling everything to find the power supply was just as loud as the two 290x cards.
 
I run a Corsair RM1000 with my 290x crossfire setup. According to Corsair Link I pull between 40-65amps depending on the game... at 65amps thats around 780watts. This is with a mild overclock(4.4), as I was having some stability issues when I added the second 290x.

Then again I'm not sure how accurate Corsair Link is... as I personally think it's a total piece of shit.
 
I just put a second OC'd 290x in my system last night and am running a 2600K at 4.2Ghz (may up it, may not) an H80i, H100i 3 SSDs, 1 HDD, SB Titanium HD, 7 fans on a Corsair HX850 and it has been stable so far. Research I did indicated it should be fine, but if I did not have the 850 already I probably would have gone higher.
 
I used the PSU in sig with a pair of unlocked 290's under water with good overclocks, never failed me. Still using it now. At the time it was on sale and I figured I might as well buy something more capable than what I thought I'd need because a power supply is something you don't want to have to change often.

I should thank [H] for the recommendation too, their review was the deciding factor for me.

http://www.hardocp.com/article/2012/09/12/enermax_platimax_1350w_power_supply_review/
 
Last edited:
Shyne151 said:
I run a Corsair RM1000 with my 290x crossfire setup. According to Corsair Link I pull between 40-65amps depending on the game... at 65amps thats around 780watts. This is with a mild overclock(4.4), as I was having some stability issues when I added the second 290x.

Then again I'm not sure how accurate Corsair Link is... as I personally think it's a total piece of shit.
Click to expand...

65 amps? if your computer is using 780 watts then thats less than 7 amps. A clothes dryer doesnt even use 65 amps
 
workshop35 said:
65 amps? if your computer is using 780 watts then thats less than 7 amps. A clothes dryer doesnt even use 65 amps
Click to expand...

He is talking about the DC amperage of the powersupply, since most of the power is pulled from the +12v rail.

We aren't talking about the 120v or 230v AC outlets.
 
1000w is in no way overkill for a heavily overclocked system with 290x CFX. I had a 750w power supply before the one in sig when running 2x 290x and it couldn't support the load. 1000w at a minimum I would say as there were instances where my system would pull over 900w.
 
My fx9370@5ghz paired with reference 290xs in cf draw about 900w from the wall depending on the game. An overclocked sandy 6 core is easily as energy inefficient as an oc'd amd 8 so 1000w psu is probably the minimum you should use especially if you want to overclock the cards, too. An 800w psu would be perfectly fine for an oc'd intel quad core.
 
I have a Corsair 850 and I am running 2 290X cards with no problem what so ever. having 2 390X's may change the story a bit so you would want the 1000 watt PSU.
 
hcforde said:
I have a Corsair 850 and I am running 2 290X cards with no problem what so ever. having 2 390X's may change the story a bit so you would want the 1000 watt PSU.
Click to expand...

op is on a sandy-e platform. its power consumption-especially oc'd to 5ghz-is easily 100w or more over your stock clocked i5. the 390xs supposedly will eat no more than the 290xs. oc'd sandy-e plus oc'd 290xs mean a 1000w psu is imperative.
 
rennyf77 said:
op is on a sandy-e platform. its power consumption-especially oc'd to 5ghz-is easily 100w or more over your stock clocked i5. the 390xs supposedly will eat no more than the 290xs. oc'd sandy-e plus oc'd 290xs mean a 1000w psu is imperative.
Click to expand...

Uhhh.........missing your point here. Didn't I say he would want the 1000W PSU?
 
It doesn't hurt to run a powersupply below 65%. Most good ones have a pretty flat efficiency curve. The positive is you should have less ripple the less % usage you are at.

Get a quality powersupply with zero fan mode and even if you go overkill on it can't hurt. Going cheap can. And overkill + zero fan mode (or whatever they call it) you might never have the fan spin up.
 
Dayaks said:
It doesn't hurt to run a powersupply below 65%. Most good ones have a pretty flat efficiency curve. The positive is you should have less ripple the less % usage you are at.

Get a quality powersupply with zero fan mode and even if you go overkill on it can't hurt. Going cheap can. And overkill + zero fan mode (or whatever they call it) you might never have the fan spin up.
Click to expand...

This^^

Buy 1KW. Buy 1.3KW. It's not going to hurt anything. Don't buy cheap though.

Another consideration is that not all PSU companies sell the same thing they send to reviewers. I've seen reports on JonnyGuru of both EVGA and Corsair having all Japanese caps on review models and Chinese caps being reported by owners. I've never seen a report of Seasonic, Antec, or Enermax doing it.

Enermax has been laying low for a while now as far as their units being reviewed. They've closed their factory and have an OEM making them. I don't know who that is though.

You can usually save a bit of money buying XFX units made by Seasonic. They seem to be identical, except for the fans. They use cheaper fans, although still good quality.

Antec's Seasonic and Delta made PSU's seem to be excellent.

You won't find any of these cheap, but they do have decent sales periodically.
 
hcforde said:
Uhhh.........missing your point here. Didn't I say he would want the 1000W PSU?
Click to expand...

Your comment intimates that he would want a kw psu for 390x crossfire. My comment suggests he needs a kw psu regardless if he ever upgrades his intended 290s. Plainly put if hes going to run an oc'd e platform system with oc'd 290s. He shouldn't use anything less than a kw psu.
 
You must log in or register to reply here.
Back
Top