SLI heat problems

[Johanmyst]

Hi there,

 

In my system I run 2 GTX GeForce 580's in SLI. Because of the motherboard not having any other PCI-e slots I am forced to place my graphics cards in the slots right next to each other, which leads to there being extremely little room for my top graphics card to suck in cool air. I do have an independent side cooler, blowing Fresh air into the side (or front?) of the graphics cards which is controlled by me. 

 

 

The sort of slot looking thingies to the right of my graphics cards are where the cool air gets blown into the case from the front. The extended panels guide the air into the graphics cards instead of into the case. To the bottom is a audio card. I can't swap the bottom graphics card with the audio card either because the graphics card is so thick, that it doesn't fit over the cables going into the motherboard at the bottom. 

 

My question is: Does anyone have an idea how I can increase performance slightly? In idle the temperatures are: Bottom Card: 58 degrees Celsius. Top Card: 87 degrees Celsius. 

And when in full use (mind you, I put the fans on the card at 85% and the intake air at 100%): Bottom Card: 95 degrees Celsius. Top Card: 99-101 degrees Celsius. 

 

Anyone any ideas? It would be greatly appreciated. 

 

[Nacho588425]

That is EXTREMELY high

 

Seriously, turn off that PC right NOW and clean the graphics cards and replace thermal compund.

 

I know Fermi is quite hot but that is just too much... even on Idle

[Nacho588425]

@Johanmyst you should follow this topic to know when people reply to it...

 

(sorry for double post, I just want him to get the notification and I don't know if he will receive it if I edit the other post)

[Johanmyst]

@Nacho588425 Cheers mate, I didn't realise you had to follow the post you made yourself, I kind of half assumed it would do that on its own. Anyway, I suppose your suggestion of changing the thermal compound is a good one. I'll go and pick up a tube today and some alcohol and get to work today or tomorrow or so. Thank you for the quick reply, even though I didn't see it immediately. 

[Aniallation]

@Nacho588425 Cheers mate, I didn't realise you had to follow the post you made yourself, I kind of half assumed it would do that on its own. Anyway, I suppose your suggestion of changing the thermal compound is a good one. I'll go and pick up a tube today and some alcohol and get to work today or tomorrow or so. Thank you for the quick reply, even though I didn't see it immediately. 

Thermal compound might bring down your temps by a few degrees but not enough to offset how hot they run. The two cards are right next to each other with barely a cm of space to draw in air, and the air that does get through that crack is practically superheated since the PCB of graphics cards also get really hot as well. 

 

Also, how good is the airflow in your case? You should really get a rear exhaust fan.

[Johanmyst]

Thermal compound might bring down your temps by a few degrees but not enough to offset how hot they run. The two cards are right next to each other with barely a cm of space to draw in air, and the air that does get through that crack is practically superheated since the PCB of graphics cards also get really hot as well. 

 

Also, how good is the airflow in your case? You should really get a rear exhaust fan.

 

Most of the air the graphics cards use gets blown in horizontally, in the pictures from the right side. If you see the funky looking nozzle-like things, they're actually the exhaust of a fan sucking air in directly from the front of the case. (thinking of it I should probably take that out and give it a thorough clean...) The sort of plastic housing you see to the left of the graphics cards, opening like a door towards the camera, is a sort of casing that goes around the Graphics cards to keep the air that gets blown in from the front going solely over the PCI slots. The rest of the air gets sucked out through the radiator at the top which isn't visible in this picture because that performs fine. The annoying thing is that no other orientation of cards is allowed in this case/motherboard so I've no choice but to put them this close together... The room between the cards is +/- 0,9 cm. It's terrible... I know... I am changing the thermal compound regardless because I do not recall it being so bad when the PC was new so I guess a redo with some Arctic Silver wouldn't hurt.

[Aniallation]

I am changing the thermal compound regardless because I do not recall it being so bad when the PC was new so I guess a redo with some Arctic Silver wouldn't hurt.

Well thermal paste I wouldn't imagine decomposes that fast, seeing the 580 isn't that old. I'd take the shroud off the GPUs and give them a thorough cleaning. 

[Kyuubixchidori]

can you undervolt the cards? are are they locked? dropped the voltage of my 7950, never hear the fans. 

[Johanmyst]

can you undervolt the cards? are are they locked? dropped the voltage of my 7950, never hear the fans. 

 

They're not locked as far as I am aware but... I'd rather not if possible, they're already lagging behind quite a bit so... 

[Kyuubixchidori]

They're not locked as far as I am aware but... I'd rather not if possible, they're already lagging behind quite a bit so... 

ah, undervolt, not underclock. graphics cards are usually given a bunch of voltage so every card is stable. which means that there is some wiggle room for your chip. dropping voltage decreases temps. 

 

most people do the opposite, overvolt a tad, it adds heat, but opens up overclocking room. in your case, you want to keep the same clockspeeds, the same performance, but essentially make the cards more efficient. 

 

 

its common with laptops to undervolt because of their weak cooling solutions. would look into it. 

[Johanmyst]

ah, undervolt, not underclock. 

 

I honestly did not know those two things wouldn't directly influence one another. Thanks for the tip, I'll be sure to check into it. 

According to MSI Afterburner my "Core Voltage (mV)" runs at 1025 mV. Any suggestions what I should bring this down to?

[Johanmyst]

@Kyuubixchidori @Aniallation @Nacho588425 Thank you for the suggestion to swap the Thermal compound. After swapping it and having the PC active for a while the idle temperatures are 49-52°C for the bottom card, and 67-71°C for the top card. This is already a LOT better than what it was before running in idle. So I assume it's probably not smart to start playing some heavy games right away, is there a benchmarking software that monitors temperature at the same time? Right now I'm using MSI Afterburner on my second monitor but I'm not sure if that's smart when you're running a benchmark. Either way, thank you for you help, it's much appreciated 

[Nacho588425]

@Kyuubixchidori @Aniallation @Nacho588425 Thank you for the suggestion to swap the Thermal compound. After swapping it and having the PC active for a while the idle temperatures are 49-52°C for the bottom card, and 67-71°C for the top card. This is already a LOT better than what it was before running in idle. So I assume it's probably not smart to start playing some heavy games right away, is there a benchmarking software that monitors temperature at the same time? Right now I'm using MSI Afterburner on my second monitor but I'm not sure if that's smart when you're running a benchmark. Either way, thank you for you help, it's much appreciated 

You could activate the on-screen overlay on MSI Afterburner

[Johanmyst]

You could activate the on-screen overlay on MSI Afterburner

 

Any idea what benchmarking software would be best suitable for this use?

[Nacho588425]

Any idea what benchmarking software would be best suitable for this use?

The best software to test your GPU temperatures is Furmark but I'm afraid that will burn down your graphics cards lol

 

Try the Unigine Valley Benchmark or the Unigine Heaven, they are both very good

[Johanmyst]

The best software to test your GPU temperatures is Furmark but I'm afraid that will burn down your graphics cards lol

 

I've heard people say not to use Furmark for specific scenarios because it'll burn down your graphics card... Why is that? What does it do differently than the others that makes it do that?

[Johanmyst]

Try the Unigine Valley Benchmark or the Unigine Heaven, they are both very good

 

I tried the Unigine Heaven and ran a few benchmarks with different fan settings. Seems like if I put the fans on the card at 75%, the fan that blows air in the front of the cards at 60% (so the machine is relatively quiet, compared to both fans at their maximum...) I run temperatures of around 85-90°C for the top car and 70-80°C  for the bottom card. Looks like the idle temperatures I got before... lol...

[Nacho588425]

I've heard people say not to use Furmark for specific scenarios because it'll burn down your graphics card... Why is that? What does it do differently than the others that makes it do that?

That is because that benchmark is designed to stress your GPU to the total maximum... but it's not very good to see how your graphics card will run while you are gaming since games dont need as much power as Furmark. The other benchmarks are actually better to see how the graphics card will perform while gaming

[Johanmyst]

That is because that benchmark is designed to stress your GPU to the total maximum... but it's not very good to see how your graphics card will run while you are gaming since games dont need as much power as Furmark. The other benchmarks are actually better to see how the graphics card will perform while gaming

 

Fair enough. Anyway I'm happy the temperature is already down quite a bit. It's still not perfect but... It's a LOT better

[Cheddle]

Glad thermal paste helped :-) my old 6870 (or 6970 or whatever) was idling at 70c...

Scraped off the crusty old stuff, replaced with genetic crap and dropped 20c and heaps of noise.

Undervolt will reduce stability so drop by 5mv increments per 60 seconds while benchmarking untill you crash then up it by 5mv, stress for as long as possible and if it crashes creep it up until your stable.

For the love of God do NOT set to apply settings on start up untill you have it stable.

I dropped 35mv on my r9 290 crossfire to run stock clocks a little cooler.

[Johanmyst]

Undervolt will reduce stability so drop by 5mv increments per 60 seconds while benchmarking untill you crash then up it by 5mv, stress for as long as possible and if it crashes creep it up until your stable.

 

For the love of God do NOT set to apply settings on start up untill you have it stable.

 

Didn't even see the button: "apply at system startup" until you mentioned it lol... Will try that. Strange thing has happened though: before I said that the core voltage was at 1025 mV, but now it defaults to 1013 mV... Is there a reason for this? And since it's stable now, should I just leave it like that?

[Cheddle]

Not sure why it is changing?

 

I havnt payed attention to the actual voltages before I only look at the offset against stock (i.e -45mv or +70mv rather than 1140mv or 1255mv)

 

if you are happy with the temps/noise and its stable then you should just leave it  B)

[Johanmyst]

if you are happy with the temps/noise and its stable then you should just leave it  B)

 

Exactly what I'll do. Thanks anyway mate