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750w psu for gtx 680 sli?

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  • Power Supplies
  • Gtx
  • SLI
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Last response: in Components
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March 25, 2012 4:25:44 AM

My system right now with a gtx 570 and an i5 2500k @ 4.3ghz is pulling anywhere from 330-360watts when running games (using a kill-a-watt to measure).

I have an antec high current gamer 750w psu.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I'm thinking of going SLI gtx 680 when ivy bridge hits in june or whenever it does. I'm guessing that with a second video card it'll pull at a maximum 600watts, probably more like 530-550 just a guess.

Would my 750w antec psu cut it do you think?

Or would it be safe to get the 900w version instead for $100?
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Or should I just swipe up this great deal on a cooler master 1200w 80 plus gold for $180 and never worry again:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

By looking at what my system is pulling I would guess that my 750w would cut it... I'm not exactly sure how psu's work though. If it's a 750w psu, 80 plus bronze let's say actually operating at it's 82% efficiency rating... can it actually supply 750watts to the components but have to pull more from the wall because of the efficiency loss?

More about : 750w psu gtx 680 sli

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a c 275 ) Power supply
March 25, 2012 4:34:52 AM

Your current psu is sufficient.
This test was conducted on an overclocked Core i7 965 / X58 system which requires more power then your platform.
http://www.guru3d.com/article/geforce-gtx-680-review/9
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Anonymous
a b ) Power supply
March 25, 2012 5:00:08 AM

lmulder said:
If it's a 750w psu, 80 plus bronze let's say actually operating at it's 82% efficiency rating... can it actually supply 750watts to the components but have to pull more from the wall because of the efficiency loss?


you will be providing your rig with 750 watts while pulling 915 from your wall.

btw, here is another review of the 680 and it looks like it draws LESS power than the 570.
http://www.anandtech.com/show/5699/nvidia-geforce-gtx-6...
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March 25, 2012 5:12:23 AM

ahhh cool, thanks.

well then I see no reason to upgrade then... system won't even be pulling 550w full load... even less if I upgrade to ivy bridge...

that's 200watts of headroom plus I'm sure this PSU has some decent head room as well.

I almost wonder if the 750w and 900w versions of these psus are the exact same with a different stamp on 'em...

Those reviews show 30-40w less for the 680 than the 570, with 2 cards that's 60-80w less, plus I'm sure moving to ivy bridge is a bit less as well. Shave 100w + off system draw versus sli 570s and sandy bridge...
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March 25, 2012 5:58:25 AM

Antec HCP PSU's have delta components, they have been tested to pull well over the stated wattage before failing, we have pushed a Antec HCP 1200 to 1700 before failure and a Quattro to 1900 before failure. Your 750 is more than enough.

I am going to say your bigger issue will be SLI scaling on 680's which seems to be a problem.
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Anonymous
a b ) Power supply
March 25, 2012 6:08:33 AM

sarinaide said:
I am going to say your bigger issue will be SLI scaling on 680's which seems to be a problem.


got a link?

or just an opinion?


i've missed ya man! :bounce: 
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a c 1217 ) Power supply
March 25, 2012 6:19:48 AM

For a system using two GeForce GTX 680 graphics cards in 2-way SLI mode NVIDIA specifies a minimum of a 750 Watt or greater power supply that has a combined +12 Volt continuous current rating of 53 Amps or greater and that has at least four 6-pin PCI Express supplementary power connectors.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Continuous Amperage Available on the +12V Rail(s) is the most important factor.

The Antec High Current Gamer Series 750W (HCG-750), with its combined +12 Volt continuous current rating of 62.5 Amps and with four (6+2)-pin PCI Express supplementary power connectors, is more than sufficient to power your system configuration with two GeForce GTX 680 in 2-way SLI mode.

There is even spare capacity to handle any overclocking you may want to perform.
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March 25, 2012 6:26:28 AM

No he's right, I've seen a few reviews where SLI scaling is an issue. However, I think that it's a driver related issue and will hopefully be taken care of in the next few months by nvidia. It looked pretty bad, as in 130% scaling in bf3 on medium settings where the 7970 had like 190% scaling. It's gotta be a poor driver issue because they just released the card...

Also, if I'm reading from my kill-a-watt meter from the comp, at let's say 85% efficiency, then my limit for the kill-a-watt meter would be around 880w, not 750w, correct? If the kill-a-watt is reading 350w, then my comp is really using 280w at 85%, right?

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March 25, 2012 6:28:51 AM

Oh wow you're running 2 480s on a 650w psu? Guess I'll be good to go lol.
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March 25, 2012 6:33:34 AM

Well it appears I am down to one 480 now, volt mod that didn't go to plan, pushing single card 3DM11 HWBOT benches I seemed to have red screen perminantly now. Ah well I guess I have incentive now to move over to new cards. Expecting to pick up two 7870's soon.
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Anonymous
a b ) Power supply
March 25, 2012 6:40:55 AM

lmulder said:
No he's right, I've seen a few reviews where SLI scaling is an issue. However, I think that it's a driver related issue and will hopefully be taken care of in the next few months by nvidia. It looked pretty bad, as in 130% scaling in bf3 on medium settings where the 7970 had like 190% scaling. It's gotta be a poor driver issue because they just released the card...


oh?

"After testing two GeForce GTX 680 cards in SLI one day after the official launch, with the first public driver I'm quite impressed. We see good SLI scaling in all our games, except for Skyrim which seems to use a quirky rendering engine that doesn't play well with multi-GPU setups."
http://www.techpowerup.com/reviews/ASUS/GeForce_GTX_680...

"Yeah... it is no surprise to see the GeForce GTX 680 perform the way it does. Ever since the release of the 400/500 series SLI performance with two cards has been great. . . .Performance wise, very little negative can be said about the GeForce GTX 680 set up in SLI."
http://www.guru3d.com/article/geforce-gtx-680-sli-revie...


"In a nut shell, nVidia GeForce GTX 680 SLI scales really, really well . ."
http://nl.hardware.info/reviews/2641/14/nvidia-geforce-...

so where did you see that there where problems?

besides:
Aside from Metro 2033, Nvidia’s newest single-GPU flagships consistently top the charts. In light of a lower price tag and fewer driver-related oddities, I wouldn’t hesitate to buy two GeForce GTX 680s instead of the two Radeon HD 7970s I purchased (and for $100 less), given an opportunity to choose again.
http://www.tomshardware.com/reviews/geforce-gtx-680-sli...
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March 25, 2012 6:43:54 AM

I can't remember the site lol, but I was just looking for bf3 scaling and it was 130% for medium settings 1920x1080 which is close to what I run on a 120hz. I noticed that toms had excellent scaling though, so it looks like the problem has already been resolved.
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March 25, 2012 6:52:14 AM







Sorry this has been derailed.
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Anonymous
a b ) Power supply
March 25, 2012 7:10:45 AM

sarinaide said:

Sorry this has been derailed.


if the "rail" was a 680 sli will beat a 7970 xfire set up in BF3 then yes.
sarinaide said:
I am going to say your bigger issue will be SLI scaling on 680's which seems to be a problem.


however the discussion was the alleged problems with sli scaling of a gtx680 set up so . . . .try again.

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March 25, 2012 7:34:01 AM

lmulder said:
I can't remember the site lol, but I was just looking for bf3 scaling and it was 130% for medium settings 1920x1080 which is close to what I run on a 120hz. I noticed that toms had excellent scaling though, so it looks like the problem has already been resolved.


Is there any reason why you want to run two 680's, I have run two 580's, 7970's and you don't get good returns on resale so you are essentially stuck with them unless you want to take the knock?

The Kepler is impressive, its also 5-6 months newer than the Tahiti and the puffing of 50% gains over the 7970 quickly went out the window, at best its 5-10% faster but also packs more expensive PCB and silicon, they intended it to market at $700-800 but had to undercut the AMD competitor due to the lack of performance to justify the cost. Essentially Nvidia are selling a expensive unit for a bellow needed price, also bear in mind the 7970's have sold by the bucket loads already so AMD can just reverse Nvidia and undercut them again. Nvidia cannot push this Unit below $500 so Nvidia have a problem marketing this generation.

If you wait it out you can get 7970's for cheaper and the cards have very little to choose between them.
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March 25, 2012 7:57:58 AM

i just came here to write
"lol"
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March 25, 2012 8:47:42 AM
Anonymous
a b ) Power supply
March 25, 2012 9:01:37 AM

Devastater6194 said:
Where did you get these graphs?

:lol: 

i just asked myself that a few minutes ago and found them here, the SAME review i used :lol: 
http://nl.hardware.info/reviews/2641/7/nvidia-geforce-g...

of course he neglected to specify the stipulations:
"Battlefield 3

On a single monitor with two GTX 680s you get much better scores in Battlefield 3 than with two HD 7970s. However, with three monitors the two HD 7970s performed better. Crossfire also scales better to more cards at that high resolution."

really the post reeks of hate. if there is valid information about hardware then post it. not skewed data that re-enforces negative and groundless opinions :p 
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March 25, 2012 2:16:13 PM

sarinaide said:
Is there any reason why you want to run two 680's, I have run two 580's, 7970's and you don't get good returns on resale so you are essentially stuck with them unless you want to take the knock?

The Kepler is impressive, its also 5-6 months newer than the Tahiti and the puffing of 50% gains over the 7970 quickly went out the window, at best its 5-10% faster but also packs more expensive PCB and silicon, they intended it to market at $700-800 but had to undercut the AMD competitor due to the lack of performance to justify the cost. Essentially Nvidia are selling a expensive unit for a bellow needed price, also bear in mind the 7970's have sold by the bucket loads already so AMD can just reverse Nvidia and undercut them again. Nvidia cannot push this Unit below $500 so Nvidia have a problem marketing this generation.

If you wait it out you can get 7970's for cheaper and the cards have very little to choose between them.


I already bought one gtx 680 and refuse to go amd because of past driver issues. Right now I mostly play Battlefield 3. The scaling in that game looks great with SLI, and I run a 120hz monitor. My goal in a constant minimum 120fps. I currently run all low settings and get at the least 90fps minimum with a gtx 570. I have a feeling the 680 will get me to that goal however possibly SLI might allow me to go a little higher with the settings.

I know that the next gen kepler is probably coming out this year as well? I might wait and see how that performs before jumping on the SLI bandwagon.

I also don't like the one or two frames of input lag SLI adds as well as the microstuttering problem. I bought this monitor for 0 input lag, the last thing I want to be doing is adding more.
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April 3, 2012 4:34:47 AM

"Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Continuous Amperage Available on the +12V Rail(s) is the most important factor.

The Antec High Current Gamer Series 750W (HCG-750), with its combined +12 Volt continuous current rating of 62.5 Amps"

SUPER NOOB Q:---I also have the Antex 750W HCG. 680 box says "min of 38 amps on the 12 volt rail" My brother has already hooked up SLI 680 for me, all good so far, but I do not know and neither does he if it is possible both of the 6pin connectors feeding each card could be on the same rail or not.

I assume it isn't, as each 12v rail is 40 amp, but I also don't want to assume when dealing with expensive parts. Obviously I know very little about this stuff. Is it possible I am overworking a single rail with two cards on the same one, or is each individual 6- pin connector on it's own seperate 40 amp rail?
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April 3, 2012 4:39:35 AM

Sorry for the double post, but are 6-pin connectors also all 12V rails? Back of box also lists 3.3v, and two 5V. I want to be sure he hasn't connected a smaller rail to one of the cards if they are somehow 6-pin connectors.
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April 13, 2012 7:25:45 PM

Best answer selected by lmulder.
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June 1, 2012 4:33:19 PM

Will a Corsair AX750 watt PSU be able to power an overclocked i5-2500k and two EVGA GTX 670 FTW graphics cards?
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December 26, 2012 11:43:13 PM

Yes
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