GTX580 SLI on 650 watts?

[houe]

okay lets see if you can understand this...YOU WILL BE PUSHING THAT PSU TOO HARD. just because it works does not mean it is smart to use that setup for anything length of time.

I'm not pushing it too hard according to seasonic's specifications.

and what is really pissing people off here is how ignorant you are acting.

Because I don't agree with you and have presented loads of evidence to support my position I'm ignorant?!?

 

[toyota]

I'm not pushing it too hard according to seasonic's specifications.



Because I don't agree with you and have presented loads of evidence to support my position I'm ignorant?!?

lol, so in your mind its not pushing it too hard as long as its not 100% maxed??? and yes, if you do not get that through your head by now then you are either ignorant or just plain trolling us.

 

[lehtv]

Because I don't agree with you and have presented loads of evidence to support my position I'm ignorant?!?

You mean evidence like this?

I'm running a tight budget otherwise yeah I'd be all over the seasonic X-850.

if your budget is tight then just wait untill you can afford the psu before getting the other gtx560 3gb card. its not like the gtx580 3gb is on sale or anthing.

Pff. You can sell the X-650 for at least $100 on ebay and buy XFX 850W 80+ silver (another Seasonic PSU) for $125 after rebate.

...

A few posts later:

I've already given up eating out for the foreseeable future to be able to fit these cards into my budget. I'll be eating mac and cheese and ramen noodles for 2-3 months lol.

If you are that poor, have you considered 2x 6970 instead?

Part of being stupid is that one doesn't know it.

 

[TemjinGold]

The sad thing is, for the close to 50% price premium on the MSIs, the OP will see barely any difference in gaming performance compared to say a normal pair of 580s.

Edit: We should let this rest. It is clear that, although s/he asked us "what we think the chances of it working are," that the OP does not care what we think unless we happened to agree with the planned course of action. This thread was not started to solicit advice, it was started to hopefully have people chime in to say it will be fine. So OP, since that's really what you wanted from this thread, here you go: You'll be fine. Feel good about the decision you made and go do it.

 

[toyota]

The sad thing is, for the close to 50% price premium on the MSIs, the OP will see barely any difference in gaming performance compared to say a normal pair of 580s.

50% over what? they are 600 bucks and regular gtx580 is 450-500 bucks isn't it? if the Op was really concerned about money then a 6950 crossfire setup for around 500 bucks total would get the job done at 1920.

 

[TemjinGold]

You can get a 580 for close to 400 on sale. $600 would represent a 50% premium over that. Even at 450, that is "close to 50%" premium.

 

[TakeNoPrisoners]

I agree if I was building this computer again and needed to pick a power supply I would probably be looking at a 850 watt unit. I'd even recommend a 850 watt to someone asking my advice on what PSU to buy. This is why every site rightfully recommends large supplies. It is the ideal and would be nice to have room for expansion and overclocking. You don't design a computer where you use 100% of the PSU - no room for expansion and upgrading. But that doesn't mean a PSU isn't fully capable of running at 100% load.

Since I already have a 650 watt supply and all power consumptions figures I've been reading do NOT indicate I'll be running above the output capacity of my supply I am inclined to believe its going to work fine. The only figures I've seen that would put me out of spec are stress testing applications (furmark etc), and even these only put me slightly above capacity (~105%). And my system probably won't quite be this high since my single card load is measuring lower than others. This is a reputable power supply and it is designed to run 24/7 at 100% load at 50C (my case will be considerably cooler). That means this supply can pull 744 watts at the wall 24/7! (No one has refuted this.) If it could not do that it would be rated as a lower watt supply. I really don't understand why you guys think its going to fail when I'm going to be running within the specs of the supply. Curious...

Note: If I see power at the wall above 744 watts then I will upgrade my power supply, but I highly doubt I am going to see that.

Your post reads like this, it can run at 100% so a miracle occurs so it can run 744 w all the time at 105%!

Just do it, we all want to see it pop, stop talking and do it. Just do it.

 

[houe]

Guys you are twisting things a bit now... All this I've said before and I think are being a bit unfair.

Toyota, don't you remember I originally went with AMD (6950) but ran into the screen tearing issue so I bailed and went to the green team. You convinced me not to get the 4870x2. Sound familiar? The only option on the AMD side was the 6990 cards which I did consider going with...

Also yes this is a bit pricier than a regular gtx580, but remember I got this because of the 3GB for 3 monitors. When you compare it to other 3GB cards its only about 30-40 more (I paid $570 shipped). Other 3GB cards are right around 550ish.

And I'm not going to run at 1920. I'm going to run at 5760.

 

[houe]

lol, so in your mind its not pushing it too hard as long as its not 100% maxed??? and yes, if you do not get that through your head by now then you are either ignorant or just plain trolling us.

That is correct.

 

[houe]

The sad thing is, for the close to 50% price premium on the MSIs, the OP will see barely any difference in gaming performance compared to say a normal pair of 580s.

My research indicates at 5760x1200 the added ram I paid for will benefit me.

 

[Arachnotronic]

Just go for it. 650 - 2*(244) = 162 W left for the rest of the system. You might get lucky?

Oh. Wait. Your CPU @ stock eats up 130W. Guess that's a mighty fine 32W left for everything else!

 

[Meghan54]

What's being left unsaid is what's happening when a power supply is pushed to its limits or close to it.

First, the OP is obsessing about the +12V rail and output and neglecting to consider that there will be some +3.3V and +5V output from the power supply. And every single watt of both those minor rails the power supply has to provide the computer is a watt less the +12V rail(s) can provide. And while it's true modern computers don't place heavy loads on the minor rails like old computers once did, they still are used, which decreases the available amount of wattage/amperage available from the +12V side.

Second, as one approaches the max rated output of a computer's power supply, the ps begins to lose its grip on voltage regulation and ripple/noise control. Granted, the Seasonic X-series is quite capable and even underrated, as is typical with Seasonic products, but even with them, once you approach max. rated capacity, voltage regulation, ripple/noise generation and efficiency all suffer.......

And while the wattage requirements listed in various charts demonstrate that dual 580s and the cpu the OP is running will just brush the max. output of his power supply, I doubt the charts demonstrate the odd spikes of increased power suck one encounters when changing scenes, loading levels, etc. And it's at those points that the power supply will undoubtedly be required to put out more than its rated capacity, even only briefly.

And in those situations, the unit will produce worse than charted ripple/noise generation, lose a bit of control on its voltage regulation, etc. The upshot of that will be components that have to deal with being presented an electrical signal that's dirtier than normal....sagging voltages, more ripple. And while the Seasonic will probably produce over its capacity and remain in ATX spec, the closer to the upper limits of the spec it gets means the motherboard and gpu VRM's will have to work harder to correct for that. This means the components attached can possibly end up with a shorter life span than normal.

I know what I've presented may be dismissed as being "theoretical", but in practice it happens. And with every mV of ripple increase or mW of power sag that the power supply has as it approaches capacity and/or exceeds it means the attached components "struggle" a tad more to maintain stability, esp. when overclocking any component, like the cpu or gpus. Overclocking those components makes them much more sensitive to variations/anomalies in their electrical supply.

Of course, probably the worst thing that'll happen when the OP finally gets his 580 SLI setup going with that power supply is random shut downs during heavy game play. I do hope Seasonic's OCP will kick in appropriately.

Maybe I'm just too old school about things, but I'm one that doesn't like pushing a power supply routinely beyond around 70% of rated capacity. That's about the end of their best efficiency rating, and the electrical output is still not being compromised at all by running at full tilt. Of course, I do remember the explode-a-matic Antecs of yesteryear, so maybe I'm just a little over cautious, but I've managed to keep a Corsair 620HX in service for almost 5 years (bought it when the 620's first hit the market) and through four different setups....and never had a problem. Of course, I'll admit it's currently being used in a relatively low power system right now (an oc'd i5 750, a 6950 2GB video card, 8GB RAM, 2 hd's), but it's almost out of warranty and I have no qualms about it staying in service at all.

But what I really think will happen to the OP......either shut downs in game play, as I mentioned before, or his overclocks on his cpu won't be as high as he wants or won't be stable under high stress, again producing shut downs. I really doubt the magic smoke will leave the power supply.....or motherboard or gpus. Just will have an unstable system at full stress.

 

[djpheer]

So I am the person from the other thread on overclock.net that has actualy done this. You guys can say what you want about me understating the wattage but I can provide at least a small bit of proof. Here is a video I *just* took of me loading up a game of bad company 2 and playing around for a bit. You will have to take my word on the fact that this machine has GTX 580's becuase my flip camera is too blurry to make it out clearly. You can also say what you want about there not being enough action on the screen or not trying other games, but I know what it reads on a day to day basis over the past couple months and this is an accurate representation. I have never peaked over 600 watts in ANY game with my 580's in SLI. I also want you to keep in mind that this is with a 120hz monitor/router/modem also connected to the APC which I have measured at exactly 50 watts draw for all 3 combined. So whatever you see in this video you can subtract 50 watts. Enjoy:


http://www.youtube.com/watch?v=-RHqrGZQC8Y



System specs are as follows:

2600K @ 4.5 @ 1.36v under load (using offset voltage)
P8P67 PRO
4x2GB GSKILL DDR3 1600
2xGTX580 in SLI (evga/asus reference models)
1x 60gb ocz agility 2 ssd
1x 1tb wd caviar black hd
HAF 932 case with default fan configs

Here is my thread on overclock.net

http://www.overclock.net/power-supplies/1076674-doing-unthinkable-gtx580-sli-650-watt.html

I would also like to mention that if I overclock the cards to 875mhz using 1100mv instead of default of 1000, my average wattage skyrockets from 550-600 watt power draw from the wall to 700-750 watt power draw from the wall. Still actualy within the specs of the power supply since 50 of that is monitor/other components, but none the less it is a huge increase when overclocking the cards.

 

[houe]

So I am the person from the other thread on overclock.net that has actualy done this. You guys can say what you want about me understating the wattage but I can provide at least a small bit of proof. Here is a video I *just* took of me loading up a game of bad company 2 and playing around for a bit. You will have to take my word on the fact that this machine has GTX 580's becuase my flip camera is too blurry to make it out clearly. You can also say what you want about there not being enough action on the screen or not trying other games, but I know what it reads on a day to day basis over the past couple months and this is an accurate representation. I have never peaked over 600 watts in ANY game with my 580's in SLI. I also want you to keep in mind that this is with a 120hz monitor/router/modem also connected to the APC which I have measured at exactly 50 watts draw for all 3 combined. So whatever you see in this video you can subtract 50 watts. Enjoy:


http://www.youtube.com/watch?v=-RHqrGZQC8Y



System specs are as follows:

2600K @ 4.5 @ 1.36v under load (using offset voltage)
P8P67 PRO
4x2GB GSKILL DDR3 1600
2xGTX580 in SLI (evga/asus reference models)
1x 60gb ocz agility 2 ssd
1x 1tb wd caviar black hd
HAF 932 case with default fan configs

Here is my thread on overclock.net

http://www.overclock.net/power-supplies/1076674-doing-unthinkable-gtx580-sli-650-watt.html

I would also like to mention that if I overclock the cards to 875mhz using 1100mv instead of default of 1000, my average wattage skyrockets from 550-600 watt power draw from the wall to 700-750 watt power draw from the wall. Still actualy within the specs of the power supply since 50 of that is monitor/other components, but none the less it is a huge increase when overclocking the cards.

Hey! When contemplating this feat i saw your thread. Anyway its interesting the difference in how you were received vs how I was received here. Anyway thanks for the video - looks good! Great to hear from someone who has done it. A lot of nay sayers don't believe its possible.

 

[Termie]

Hey! When contemplating this feat i saw your thread. Anyway its interesting the difference in how you were received vs how I was received here. Anyway thanks for the video - looks good! Great to hear from someone who has done it. A lot of nay sayers don't believe its possible.

While that is an impressive feat, remember that his cpu is much more efficient than yours. To get close to equivalent performance, you're talking 100w more, and while you may not be looking for an extreme overclock, as I mentioned before, dual 580s will be bottlenecked on a stock 930.

Here's some info on power draw:

http://www.anandtech.com/show/4083/...core-i7-2600k-i5-2500k-core-i3-2100-tested/21

Extrapolating from those numbers, I'd say your cpu at stock draws about the same as his overclocked 2600k.

 

[kevinsbane]

Lots of text about PSU behaviours at high capacity

Your points make sense theoretically, but in practice they will not be an issue for the X-650. This review at Jonnyguru by Oklahoma Wolf shows that PSU voltages on the X-650 do not sag appreciably, even at 100% capacity. It goes from 12.25V at 20% load to 12.14V at 100%, a drop of 0.11V. Voltage regulation will not be an issue even up to 100% capacity, especially given that ATX spec is is a minimum of 11.4V (+/-5%).

Ripple and noise is also not an issue, as the very next page shows the X-650 ripple value at extremely low levels; in fact, it's better to load it at 100% than 20%.

The concern about ripple and voltage regulation is generally good practice, but the X-650 is not affected by it, even up to maximum capacity. According to the review, running your X-650 at <20% load is worse for your computer than running it at 100%. Hum. Now I feel a need to boost up my power consumption... I'm running my X-650 at <10% load... (50 watts idle... yes, I know I don't need an 650watter for it.)

The only real concern you might have with this power supply is whether or not running a PSU (even of this calibre) at 100% for hours is detrimental to the health of the PSU. Considering the quality of the X-series (SPCR ran an X-400 fanless at 100%, at 55 degrees C+ input air for 15 hours straight, and it ran fine and dandy) I personally think it can handle it.

 

[lehtv]

It goes from 12.25V at 20&#37; load to 12.14V at 100%, a drop of 0.11V

That's actually an improvement, not a drop in voltage regulation...

 

[BFG10K]

I know it has plenty of reserve. I still prefer to keep a gap between the rated wattage and the actual power consumption, just to preserve longevity.

That’s great but it’s exactly that – your preference. That doesn’t always translate into reality.

I didn't imply nVidia's recommendations were based on Seasonic's heavily overspecced units. I asked whether they're based on crap-end units, i.e. PSUs that are not capable of their rated wattage, rather than PSUs that are. Seasonic's PSUs, I know, are capable of outputting more than their rated wattage (though not designed to do so continously, I should add).

I’ve already been through this. A stock GTX580 system doesn’t come close to drawing 600W, yet they’re asking for a 600W PSU. Thus according to their rating my 560W can’t handle the card, yet the PSU isn’t even breaking a sweat.

So obviously they’re rating based on PSUs that can’t handle full rated load and/or units that can only reach full load by unrealistically loading the 3.3V/5V.

Are you kidding me? Where did I ever say I'd recommend anyone even buying, not to mention powering up, a crappy Deer unit? On what basis do you, again, extrapolate that what I'd do with a Seasonic PSU applies to all other PSUs as well? I've never said anything like that. The answer to your question is of course "no".

Where did I say you recommended buying one? I said you treated them the same based on labels.

Let’s say hypothetically you restrict yourself to a 75% load (300W from a 400W unit). Let’s also say hypothetically a lesser unit can handle 350W while the Seasonic has components that can handle 700W and has an OPP trip point of ~600W (both are true).

Would you restrict yourself to a 300W load on both PSUs because both have a 400W label?

Sigh.

Indeed; it’s a sad state of affairs when I have to explain something as elementary as “back”.

 

[BFG10K]

First, the OP is obsessing about the +12V rail and output and neglecting to consider that there will be some +3.3V and +5V output from the power supply. And every single watt of both those minor rails the power supply has to provide the computer is a watt less the +12V rail(s) can provide. And while it's true modern computers don't place heavy loads on the minor rails like old computers once did, they still are used, which decreases the available amount of wattage/amperage available from the +12V side.

The amount on the 3.3V/5V is trivial in a modern system. You might get a couple of watts from HD/USB but that’s about it. There’s a reason quality modern PSUs are designed to output pretty much their entire rated wattage on the 12V while the minor rails are treated as second-class citizens.

Kevinsbane has already made some good comments about the rest of your points.

Bottom line: I believe the particular PSU being discussed can handle the OP’s situation, as long as he doesn’t overclock anything or runs Furmark. For the rare times he might spike over 650W (DC) the PSU has ample reserve to handle it.

 

[lehtv]

@BFG10K it sounds like you're just not familiar with the concept of safety margin.

Would you restrict yourself to a 300W load on both PSUs because both have a 400W label?

Again... Where did I ever say I'd even recommend powering up a unit that can only handle 350W out of its 400W wattage? You're still extrapolating.

To answer your question precisely, I would restrict myself to 0&#37; load on the PSU that can only do 350W. On the seasonic, I'd prefer to keep it under its rated wattage even if its very underrated. I acknowledge that it's POSSIBLE to run it at its rated wattage for long periods of time, I still wouldn't RECOMMEND it.

Indeed; it&#8217;s a sad state of affairs when I have to explain something as elementary as &#8220;back&#8221;.

I can only watch from aside as you attempt to look smart by being a condescending prick. Sad state of affairs indeed