Goin tri sli, how much juice is needed?

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Hey, i was looking to add another 2 gtx 670 ftw cards to my rig, and i was wondering how much power that i needed, i have a 750w psu now, but i dont think that will cover it.
 

LigTasm

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Ran tri-sli 670's with a heavily OC'd 2011 setup on a 750w NZXT PSU, worked fine. Pulled ~650w from the wall during benches, closer to 500 gaming. Buy a 1kW if it makes you sleep better at night but you probably don't need it.
 
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750W will most lilkely be enough to power three 670 GTX video cards, but if you want a little breathing room then get a descent 850W PSU.

As you can see here, SLI 680s consume less than 550W (At the wall)


Since we know the PSU used in that system has a power efficiency rating of ~90%, we can conclude that the PSU's output is close to 500W and since the video card isn't the only thing in the system drawing power and we know from the diagram that an idle system with no video card consumes 67W, we can assume that a system powering two video cards consumes at least 100W, so we're looking at cards that draw 200W each, so add that back to the 500W rating and we're at 700W of PSU output powering three 680 GPUs.

Since we know the power consumption between a 670 and 680 is pretty close, we can conclude that yes a 750W PSU should be enough for three 670 GPUs; but if it were me I'd go with an 850W PSU.
 

Jorona

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GTX 670s at worst use 185w per card. So you have ~600w there. The remaining system will pull another 150-200w. So were at ~850. Give yourself 10% overhead, and you end up at the 950w point.

So any solid 950w+ PSU should handle your system just dandy. Seasonic Platinum 1000w, XFX 1000w, Kingwin LZP-1000 all come to mind.
 
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GTX 670s at worst use 185w per card. So you have ~600w there. The remaining system will pull another 150-200w. So were at ~850. Give yourself 10% overhead, and you end up at the 950w point.

So any solid 950w+ PSU should handle your system just dandy. Seasonic Platinum 1000w, XFX 1000w, Kingwin LZP-1000 all come to mind.

You suck at math.

185W * 3 = 555W

555W + 200W = 755W

1.10 * 755W = 830W
(10% of 755W + 755W)

How the hell did you conclude 950W? :confused:
 

Jorona

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You suck at math.

185W * 3 = 555W

555W + 200W = 755W

1.10 * 755W = 830W
(10% of 755W + 755W)

How the hell did you conclude 950W? :confused:

Because, yes, I suck at math...

I rounded up on the 185 to 200, but the extra 50w is because I am infact dumb.

If he OCs that 670 it could get close to 200w is the reason for the rounding. So my math then puts him at about 880w. Seeing as there are very few quality 900w units, I'm gonna go ahead and stick to my unit reccomendations though.
 

Dan_D

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I would grab a 1kw unit to be on the safe side. I know I'm under the 1kw mark on mine as my UPS would go apeshit if I hit 950w and alarm like crazy. Aside from that I've not checked the actual power consumption.
 
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Still not buying that it needs even 950W...



Here we can conclude that a max overclocked 670 consumes 325W of power, but lets round up to 330W. So lets forget system power and just multiple that 3 times. 990W at the wall.

We know the PSU used in that test setup is the Cougar GX 900W, therefore we know it has an 87% effeciency rating we can then conclude that 330W at the wall is really 288W at the wall times three is 864W. So three complete systems will consume 990W at the wall or 864W post PSU.

Still not buying that it needs 950W to power three GTX 670s.
 

LigTasm

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Because, yes, I suck at math...

I rounded up on the 185 to 200, but the extra 50w is because I am infact dumb.

If he OCs that 670 it could get close to 200w is the reason for the rounding. So my math then puts him at about 880w. Seeing as there are very few quality 900w units, I'm gonna go ahead and stick to my unit reccomendations though.



I still don't feel like the 750w would be a problem, execpt now that I think about it, it probably doesn't have enough PCI-E plugs for three cards. I don't like using adapters at all, so it may make sense to get a bigger unit in that case. Being on the safe side never hurts, I just hate replacing hardware that could possibly do the job just fine.
 

Dan_D

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Still not buying that it needs even 950W...



Here we can conclude that a max overclocked 670 consumes 325W of power, but lets round up to 330W. So lets forget system power and just multiple that 3 times. 990W at the wall.

We know the PSU used in that test setup is the Cougar GX 900W, therefore we know it has an 87% effeciency rating we can then conclude that 330W at the wall is really 288W at the wall times three is 864W. So three complete systems will consume 990W at the wall or 864W post PSU.

Still not buying that it needs 950W to power three GTX 670s.

Those configuratons are also lean. They don't have tons of hard drives or SSD's in the mix. I think those numbers represent a best case scenario with regard to power consumption. I generally base my power supply needs on the max TDP of all hardware save for the processor which I allocate a fair amount over the mark to cover for overclocking. We know these things rarely hit their TDP's but I plan for it to happen on occasion.
  • 77watts for Ivy Bridge +50 for overclocking
  • 30 watts for the motherboard.
  • 50 watts for miscellaneous fans
  • 30 watts per drive
  • 20 watts for an optical if needed
  • 250 or so watts per card (assuming something realy high end)
So your looking at 537 watts for all of that assuming at least two drives. The numbers are certainly conservative I'd agree but it's better to have more than you need rather than less.
 

Jorona

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Still not buying that it needs even 950W...



Here we can conclude that a max overclocked 670 consumes 325W of power, but lets round up to 330W. So lets forget system power and just multiple that 3 times. 990W at the wall.

We know the PSU used in that test setup is the Cougar GX 900W, therefore we know it has an 87% effeciency rating we can then conclude that 330W at the wall is really 288W at the wall times three is 864W. So three complete systems will consume 990W at the wall or 864W post PSU.

Still not buying that it needs 950W to power three GTX 670s.

You're working with full system numbers there. Thats also not max load. I'm talking furmark and Prime95 running, or even folding. Is he likely ever to hit that kind of load? No. Thats how I recommend PSUs though. Get the Maximum theoretical load, add 10-15% and then suggest a couple of quality units that will do the job. Go look in the PSU section, I do this all the time.

90% of the time, yes, his current PSU will be sufficent. That being said, in that 10% that its not, he risks damaging his system with either high ripple or poor voltage regulation.

Alittle bit of headroom on the PSU is always healthy. It's not like I'm suggesting he get a pair of 1.6Kw PSUs. I'm suggesting he give himself some cushion. Never know when you might get the urge to start folding.
 
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Yeah, right now my psu only has enough connectors for two cards, but i think i have enough molex to power two adapters. I dont know, might as well get a hx1000 if they make those
 

Climber

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Read his signature.

corsair tx750m psu

Duh. Didn't bother to check it. With that said you should be OK but you'll be pushing it. It seems like a waste to step up just 100watts so I'd recommend if the money is in your budget grab a quality 950 or 1k unit and call it good.
 

Jorona

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They do make HX1050s, but I'm not terribly sure I'd recommend it. There are better performing supplies for less money.

The Seasonic X-1050 is fully modular (The HX is Semi-Modular) and cheaper. The Seasonic Platinum 1000 is also fully modular, cheaper and has better efficiency. The Silverstone Strider Gold Evolution, The FSP Aurum Gold, etc. etc. etc.
 

SticKx911

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why not just sell your 670 and buy a 690? lol or pick up a 790 when they come out.
you guys must not have to pay your own power bills. ;)
1kw is like running your microwave the whole time your gaming. haha.

< jealousy talking...thats all.
 
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Those configuratons are also lean. They don't have tons of hard drives or SSD's in the mix. I think those numbers represent a best case scenario with regard to power consumption. I generally base my power supply needs on the max TDP of all hardware save for the processor which I allocate a fair amount over the mark to cover for overclocking. We know these things rarely hit their TDP's but I plan for it to happen on occasion.
  • 77watts for Ivy Bridge +50 for overclocking
  • 30 watts for the motherboard.
  • 50 watts for miscellaneous fans
  • 30 watts per drive
  • 20 watts for an optical if needed
  • 250 or so watts per card (assuming something realy high end)
So your looking at 537 watts for all of that assuming at least two drives. The numbers are certainly conservative I'd agree but it's better to have more than you need rather than less.

Since we really wanna get technical, lets not forget that hard drives and motherboard use more than just the 12v rail, they also use the 5v and 3v rail. His PSU has 62A on the 12v rail. That's good for 744W, 30A on the 5v RAIL which is good for 150W and 30A on the 3.3v rail good for 99W.

Fans do NOT take that much power at all. 50W for fans? Wow. A single 120MM fan consumes like .5A of power, that's 6W. 50 / 6 = almost 8.5 case fans. That's a lot of case fans. 80MM fan? Yeah somewhere along .2A of power. That's less than 3W. 50W is rather high, but whatever.

30W PER hard drive? Holy cow. Hard drives barely draw 1A on the 12v rail and 1A on the 5v rail. That's 17W between the 12v and 5v rails respectively and that's aiming high. Enough speculating, lets look and see exactly what HDD the OP is using and what kind of power it does draw.

1TB Western Digital Black drive. It has a rating of .55A on the 12v rail and .68A on the 5V rail. That's 6.6W @ 12v and 3.4W on the 5v rail. 10W total from the HDD. How did you get to 30W I have no idea.

His SSD; 128gb samsung 830 ssd is rated at 1.6A on the 5V rail. That's 8W @ 5v.

OOD? Well I couldn't find a good detailed picture showing the power rating on Newegg, so I'm pulling one of my OODs out to look. Its a Lite-on BD-ROM drive and it's power ratings are 1.5A on the 12v rail and 1.5A on the 5v rail. (I looked at my DVD burner and it also had the same power rating) So we're looking at 18W + 7.5W which means that's 25.5W, above your "guesstimate" rating of 20W.

250W per card? 670 GTX video cards do not consume 250W each. It's closer to a number BELOW 200W. As someone has already said in this very topic that running 3 670s on a 2011 setup that consumes more power than an 1155 setup. During BENCHMARKS which stress the system more than just gaming alone he only pulled 650W AT THE WALL. Again you're ASSUMING something really high end? Why are you assuming when the OP specifically stated the 670 GTX card.

I still stand behind my recommendation that 750W is plenty for the OP, if he wants to sleep better at night then go for an 850W PSU.

You're working with full system numbers there. Thats also not max load. I'm talking furmark and Prime95 running, or even folding. Is he likely ever to hit that kind of load? No. Thats how I recommend PSUs though. Get the Maximum theoretical load, add 10-15% and then suggest a couple of quality units that will do the job. Go look in the PSU section, I do this all the time.

90% of the time, yes, his current PSU will be sufficent. That being said, in that 10% that its not, he risks damaging his system with either high ripple or poor voltage regulation.

Alittle bit of headroom on the PSU is always healthy. It's not like I'm suggesting he get a pair of 1.6Kw PSUs. I'm suggesting he give himself some cushion. Never know when you might get the urge to start folding.

So you regularly recommend way more power than the user needs? :rolleyes: Even at full load, with benchmarks a 2011 setup with three 670s was drawing around 650W at the wall... Guess the person who posted that was lying and/or didn't know how to full stress the system with benchmarks?
 
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why not just sell your 670 and buy a 690? lol or pick up a 790 when they come out.
you guys must not have to pay your own power bills. ;)
1kw is like running your microwave the whole time your gaming. haha.

< jealousy talking...thats all.

That's not entirely true either. Just because you have a 1Kw PSU doesn't mean the system is drawing that much power every time you are gaming.
 
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alright, thanks, i'll probably look at one of those seasonic x 1050s just for my personal satisfaction, and who knows, i might be pulling it for a new build in a few years.
 
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alright, thanks, i'll probably look at one of those seasonic x 1050s just for my personal satisfaction, and who knows, i might be pulling it for a new build in a few years.

Fair enough.

Do note that systems are using less power than previous generations, unlike the old trend where they were using more and more power. ;)
 

Dan_D

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Snip...........

Again I did estimate high. I said as much. I wasn't sure of the precise fan power and hard drive power numbers. I had used a vague recollection of those numbers. Not sure where I got that from. Again I still stand by the addage better to have too much vs. not enough. I'm not saying you need a 1200watt PSU but 900-1,000watts for 3-Way SLI is certainly within reason.

That's not entirely true either. Just because you have a 1Kw PSU doesn't mean the system is drawing that much power every time you are gaming.

Your system will only use what is being drawn by the components. If you have a 1200watt PSU and you've only got enough components to draw 750watts, that's all it will pull.
 
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Again I did estimate high. I said as much. I wasn't sure of the precise fan power and hard drive power numbers. I had used a vague recollection of those numbers. Not sure where I got that from. Again I still stand by the addage better to have too much vs. not enough. I'm not saying you need a 1200watt PSU but 900-1,000watts for 3-Way SLI is certainly within reason.

I'm not saying it's not within' a reason; I'm just pointing out that it's most likely not needed. Why spend the money when you don't need to? Is the only point I am trying to make. :)

With that being said, the OP is going with a 1050W unit; so no matter what he does he will be fine. (Even if he does install 30 case fans. :p)
 

QwaarJet

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alright, thanks, i'll probably look at one of those seasonic x 1050s just for my personal satisfaction, and who knows, i might be pulling it for a new build in a few years.

If you do go that route and are not in an extreme rush, check out Amazon's warehouse deals.

http://www.amazon.com/gp/offer-list...sr=8-1&keywords=seasonic+1050x&condition=used

they have a couple for $170-ish, slightly cheaper than the avg online.

I scored the same power supply for $130 three months ago in "like new" condition. The box had never been opened, the packaging just wasn't in *mint* condition, but I've purchased new items in worse packaging condition..... Great PSU, extremely quiet.
 

Jorona

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So you regularly recommend way more power than the user needs? :rolleyes: Even at full load, with benchmarks a 2011 setup with three 670s was drawing around 650W at the wall... Guess the person who posted that was lying and/or didn't know how to full stress the system with benchmarks?

... I don't see how I'm recommending more then he needs. You say 850. I'm saying 880. There's no truly solid 900-950w units, so I'm recommending 1000w units because they perform well. You need to ease up man, you're getting really bent outta shape.
 

K1tty

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Well, I can attest to the Kingwin LZP-1000's awesomeness. I think there's a promo code on Newegg right now for it. I'm no where near fully utilizing it... just happened to get a good deal and was planning for the future.
 

LigTasm

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... I don't see how I'm recommending more then he needs. You say 850. I'm saying 880. There's no truly solid 900-950w units, so I'm recommending 1000w units because they perform well. You need to ease up man, you're getting really bent outta shape.


Isn't there a NZXT Hale-something 900W? I have the 850W and it is very nice. Also comes in white, which is important :D
 
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... I don't see how I'm recommending more then he needs. You say 850. I'm saying 880. There's no truly solid 900-950w units, so I'm recommending 1000w units because they perform well. You need to ease up man, you're getting really bent outta shape.

First off, my 850W recommendation is you're 900-950W equivalent recommendation. You think he needs 880W, I've proven that he needs ~700W on his setup therefore 750W should handle it; however IF the OP should want to purchase a new PSU then 850W is all he would need.

Doesn't really matter since the OP is going with a 1050W anyway.

o_O. Bent out of shape? Ha. I'm just proving my point with correct (;)) math & real world usage; not speculations or assumptions. If I am presenting my point of view too harshly, then I apologize as it's not my intentions. Just letting the OP know that he doesn't need to spend the money.
 

Jorona

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First off, my 850W recommendation is you're 900-950W equivalent recommendation. You think he needs 880W, I've proven that he needs ~700W on his setup therefore 750W should handle it; however IF the OP should want to purchase a new PSU then 850W is all he would need.

Doesn't really matter since the OP is going with a 1050W anyway.

o_O. Bent out of shape? Ha. I'm just proving my point with correct (;)) math & real world usage; not speculations or assumptions. If I am presenting my point of view too harshly, then I apologize as it's not my intentions. Just letting the OP know that he doesn't need to spend the money.

Hey now, already admitted I made a mistake. Also, if you go back and read, I'm saying 880 including the 10% overhead. I still think you're making a mistake by saying he's ok with his 750w unit though. 90% of the time, you're right, he'd be okay. He will max it out if he were to LinX and Furmark at the same time or if he chose to start folding.

GTX 670: 186w
http://www.techpowerup.com/reviews/MSI/GTX_670_Power_Edition/26.html

His Mobo with with a 3770k (maybe 5w difference between 3570 and 3770k): 145w
http://www.techpowerup.com/reviews/Biostar/Hi-Fi_Z77X/8.html

10w for the HDD (which isn't spin up load btw, that can easily exceed 30w), 0w for SSD (not on 12v rail), and 18w for the ODD. So we have another 28w there on storage.

His case comes with 3 fans, 2x120mm and one 140mm. NZXT rates the 120mm at a touch less then 4w per. The 140 is about 7w. So we have another 15w in fans. Theres also a fan controller in the Phantom 410, which I'm sure isn't 100% efficent, so lets call that 15w 20w. Sound fair?

751w is now what I come out with when we go comepletely batty nitpicking bullshit. Now add on that touch extra for the video cards I originally said I did, and *GASP*

We're at 793w. Add in the 10% overhead. And we're at 872w.

I think you're wrong ;), and now I've proven my point with math AND references.
 

Dan_D

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I thought I had recalled something about drives hitting 30watts on spinup or something.
 
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Hey now, already admitted I made a mistake. Also, if you go back and read, I'm saying 880 including the 10% overhead. I still think you're making a mistake by saying he's ok with his 750w unit though. 90% of the time, you're right, he'd be okay. He will max it out if he were to LinX and Furmark at the same time or if he chose to start folding.

GTX 670: 186w
http://www.techpowerup.com/reviews/MSI/GTX_670_Power_Edition/26.html

His Mobo with with a 3770k (maybe 5w difference between 3570 and 3770k): 145w
http://www.techpowerup.com/reviews/Biostar/Hi-Fi_Z77X/8.html

10w for the HDD (which isn't spin up load btw, that can easily exceed 30w), 0w for SSD (not on 12v rail), and 18w for the ODD. So we have another 28w there on storage.

His case comes with 3 fans, 2x120mm and one 140mm. NZXT rates the 120mm at a touch less then 4w per. The 140 is about 7w. So we have another 15w in fans. Theres also a fan controller in the Phantom 410, which I'm sure isn't 100% efficent, so lets call that 15w 20w. Sound fair?

751w is now what I come out with when we go comepletely batty nitpicking bullshit. Now add on that touch extra for the video cards I originally said I did, and *GASP*

We're at 793w. Add in the 10% overhead. And we're at 872w.

I think you're wrong ;), and now I've proven my point with math AND references.

http://www.guru3d.com/articles_pages/geforce_gtx_670_2_and_3way_sli_review,4.html

Because 3 670s in Tri-SLI consumed 583W AT THE WALL, which means output from a PSU is less and this was benched on an Core i7 965 / X58 system that is more power hungry than an i5 3570k.

They even recommend 850W PSU, but only because of shitty PSUs. In reality, a solid 750W unit will power his system.

Like I said before.
 

Jorona

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http://www.guru3d.com/articles_pages/geforce_gtx_670_2_and_3way_sli_review,4.html

Because 3 670s in Tri-SLI consumed 583W AT THE WALL, which means output from a PSU is less and this was benched on an Core i7 965 / X58 system that is more power hungry than an i5 3570k.

They even recommend 850W PSU, but only because of shitty PSUs. In reality, a solid 750W unit will power his system.

Like I said before.

They are using a game. It says so in their header. I'm talking Furmark or Folding load. Harder on the card then any game out there. Gaming doesn't put the CPU at full bore aswell. They don't list if they're using a quality meter. If its a kill-a-watt then those numbers are almost guarenteed to be false.

Like I keep saying 90% of the time, you're right. It'll be fine. You have to conceed that at a maximum load, he will be pulling more then that supply is rated for. Will it likely be fine? Sure. It's not a good idea to run a PSU at full bore all the time though, thus the 10% overhead I add in. My math is correct. My sources are reliable. What more do you want?
 
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