Is it normal for vastly different load temps in SLI?

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Svengali

Limp Gawd
Joined
Mar 13, 2006
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I have a 7900GT SLI set up and on idle the temps are vastly different (I do have a PCI Slot Fan under my GPU2) but im not sure how much a difference that really makes.

Anyways the idle temps are pretty different, in fact my stupid GPU1 idles at anywhere from 55-60C depending on room temperature and all that, but GPU2 idles at 45-50 (mainly around 45-47)

Anyways when I play games the temp difference is immense. GPU2 will sit at like 51C and GPU1 will fly up to 72-75C.

Whats the deal? Is this normal?
 
that's pretty normal for an average (meaning "stock") air cooled setup... hitting the 70s is ok.. it's warm, but still ok.. for the 7900s.. if you start seeing mid to upper 80s you might want to look into getting side fan getting air between the cards.. the bottom card will always have a tendency to heat up the top card because of the heat pooling between the cards in SLI.. so trying to blast that heat away with side fans and such seems to work well..

PS: a side fan in combination with a 3rd party cooler for the card for the top card (or even both if you want to) would be ideal for great air cooling performance.. the Zalman vf700 and 900s are very nice for 7900 series cards. but I wouldn't worry about that unless you wanted to vmod and/or highly OC the cards.
 
Many times when you have two video cards installed there will be a difference in temps between them. Usually GPU1 will run warmer as its’ air flow is hindered by GPU2. As revenant stated if you temps get too high you might want to look into more case cooling, but right now your temps look good.

XFX Support
 
XFXSupport said:
Many times when you have two video cards installed there will be a difference in temps between them. Usually GPU1 will run warmer as its’ air flow is hindered by GPU2. As revenant stated if you temps get too high you might want to look into more case cooling, but right now your temps look good.

XFX Support
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My vendor didn't feel the same (Velocity Micro) when I called them and they want to send me out a replacement card...I was merely curious about what they thought about this and they seemed to think the card was straining too much. She was surprised I wasn't artifacting at these temps.
 
Well I can’t speed for all manufactures of course, but for our 7900GT cards the max temp before the card slows itself down to prevent damage is 125 degrees Celsius (you can check this by opening the Nvidia control panel, 3d setting, monitor temps). If your card it getting a load temp of 75 degrees it should be well with in operating temps, but then again like I stated I can’t speak for all manufactures. Keep us posted if the replacement card runs cooler?

XFX Support
 
No problem, I'll definitely post back once I get the replacement card. Hehe im surprised an XFX Support guy is interested. (The cards are from eVGA)
 
mine does that too. try taking off the side panel and laying the case on its side. the lower gpu shouldnt dump so much heat into the upper one.
 
Svengali said:
(I do have a PCI Slot Fan under my GPU2)
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I think that might be causing the heating. Your gpu sucks air in to cool. The slot fan is pushing air out and away from the card. I had the same problem. My car would get upto 65c load with the slot fan. Took it out and now my temps at 58c load. Try removing and see what happens. O yeah, those slot fans suck.
 
XFXSupport said:
Many times when you have two video cards installed there will be a difference in temps between them. Usually GPU1 will run warmer as its’ air flow is hindered by GPU2. As revenant stated if you temps get too high you might want to look into more case cooling, but right now your temps look good.

XFX Support
Click to expand...

just a note, the order will not always be like that.. in the BTX config (up-side-down from ATX) GPU2 will usually run warmer as it's the "top" card in that config.. that's why I like to just say "top" and "bottom".. anyways.. I really like the BTX config as it allows the cards to be installed with their tops facing up.. I know it seems to have very little real world affect on cooling, but heat rises, and I just like having these hot running cards right side up so the heat easily travels up into the sinks.. :)

haadij404 said:
I think that might be causing the heating. Your gpu sucks air in to cool. The slot fan is pushing air out and away from the card. I had the same problem. My car would get upto 65c load with the slot fan. Took it out and now my temps at 58c load. Try removing and see what happens. O yeah, those slot fans suck.
Click to expand...


I have the opposite experience.. the slot blower I have pulls the hot air away from the vented portion of the card and expells it out side of the case.. the heat coming out of it is very much warmer than the air coming out of the card's exhaust port.. I got 5c temp drops across the board (load and idle) with the blower in.. you want to make sure your blower is installed to that it's sucking air away from the heat vents and putting it outside the case for optimal performance..
 
revenant said:
just a note, the order will not always be like that.. in the BTX config (up-side-down from ATX) GPU2 will usually run warmer as it's the "top" card in that config.. that's why I like to just say "top" and "bottom".. anyways.. I really like the BTX config as it allows the cards to be installed with their tops facing up.. I know it seems to have very little real world affect on cooling, but heat rises, and I just like having these hot running cards right side up so the heat easily travels up into the sinks.. :)




I have the opposite experience.. the slot blower I have pulls the hot air away from the vented portion of the card and expells it out side of the case.. the heat coming out of it is very much warmer than the air coming out of the card's exhaust port.. I got 5c temp drops across the board (load and idle) with the blower in.. you want to make sure your blower is installed to that it's sucking air away from the heat vents and putting it outside the case for optimal performance..
Click to expand...

Yes I was also about to say, the slot fan does help, when I first got it it was at min speed and I cranked it to max and got about 5c temp reduction.

Also thanks for all the responses guys, guess I'll find out when the new card comes if it makes a difference.
 
XFXSupport said:
Well I can’t speed for all manufactures of course, but for our 7900GT cards the max temp before the card slows itself down to prevent damage is 125 degrees Celsius (you can check this by opening the Nvidia control panel, 3d setting, monitor temps). If your card it getting a load temp of 75 degrees it should be well with in operating temps, but then again like I stated I can’t speak for all manufactures. Keep us posted if the replacement card runs cooler?

XFX Support
Click to expand...


We've noiticed there that when the temp sensor says 90c and above that some people start seeing visual artifacts on their screen.. I think this might be the gpu core heating-up the memory? I always thought artifacts were more memory related than gpu core related. Anyways..
 
I think I'm suspiciously onto something here...I just created my own profiles for new games that the drivers don't have profiles for yet. Particularly Rainbow Six Vegas, I set an SLI Rendering Mode, and guess what? GPU2 starts working, I see the temperatures going up.

Typically when I play ANY game GPU1 temps go up and GPU2 temps just sit there. Now when I create my own SLI profile for a game the temps on gpu2 go up and as does performance.

Now many games I play already have SLI profiles from the drivers and the rendering mode is marked "Predefined"

I have a GUT feeling that NVIDIAs "predefined" mode == Single GPU Rendering

And that all this time I haven't gotten any SLI Benefit at all.

What do you think? I don't know how to manually change it from Predefined as it doesn't let me.

I'd like to see if I could change it, switch it to some different mode for some other games if performance and thus temps would go up.

Help?
 
I had the same problem. I went into Nvidia control panel > 3d settings and put in global forced split rendering. This finally got both cards to heat up in ATI tool and show performance gain.
 
Thats not really a good idea though as not all games do well with SFR. I.E. I was testing modes in particular with Rainbow Six Vegas and AFR Mode 2 gives significant performance boost, AFR Mode 1 is decent, SFR gives performance DECREASE.

If I could just figure out a way to see what is being "Predefined" for certain games -- and possibly edit that if its garbage it would be nice. Any help would be appreciated!
 
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