Evga GTX 580 Classified Ultra SLI Temp Question

[superjonesy]

I recently acquired my second Evga GTX 580 Classified Ultra and I am experiencing idle temps that boggle the mind.
My old card is installed in PCI-E Slot 2 and the new card is in PCI-E Slot 5 on the mobo.

First, my rig:

Asus P8Z68-v pro/gen3 (most recent BIOS update)
Intel i5 2500k @ 4.7ghz
16gb Corsair Vengeance DDR3 @ 1600mhz
OCZ Vertex3 120gb SSD
Seagate Barracuda 500gb 7200rpm SATA
Asus Blu-Ray Burner
Corsair H100 cpu cooler (on performance mode) with 2x Feser Triebwerk TK-123 (212 CFM) fans in exhaust at top of case.
Evga GTX 580 Classified Ultra (PCI-E Slot 2)
Evga GTX 580 Classified Ultra (PCI-E Slot 5)
OCZ ZX Series 1000W PSU (mounted to exhaust out the bottom of the case)
CoolerMaster HAF X Case (positive pressure)
Modified side panel - replaced plexi-glass window with aluminum mesh
Side Panel 200mm intake @ 110cfm
Side Panel 120mm intake @ 96cfm
Front 230mm intake @ 110cfm
Rear 140mm intake @ 60cfm
Front 140mm intake @ 60cfm

120mm GPU fan @ 96cfm - blows directly between the gpu from the rear, along the cards. (If you know the HAF X you know what GPU duct I used)
All fans are linked to controller(s), for what its worth.

Ambient temperature is around 23C

Using most recent 295 drivers

Now, the problem is that GPU1 is currently idling at 24C while GPU2 is currently idling at 39C.
I setup a custom fan profile in Precision that starts at 40C and 40% fanspeed.. and increases linearly to 100% at 90C
Under load with stress test GPU1 reaches 61C and GPU2 reaches 64C.
With BF3 on ultra GP1 reaches 55C and GPU2 reaches 57C.

The load temperatures dont bother me whatsoever, in fact I am quite pleased. However the idle temperatures bug me a great deal.

Any help? Thoughts? Advice?

Thanks in advance!

TL;DR: My 2 GTX 580 Classified Ultra in SLI have very different idle temps (Delta 15C) and I want to know why.

 

[unclejehmimah]

I recently acquired my second Evga GTX 580 Classified Ultra and I am experiencing idle temps that boggle the mind.
My old card is installed in PCI-E Slot 2 and the new card is in PCI-E Slot 5 on the mobo.

First, my rig:

Asus P8Z68-v pro/gen3 (most recent BIOS update)
Intel i5 2500k @ 4.7ghz
16gb Corsair Vengeance DDR3 @ 1600mhz
OCZ Vertex3 120gb SSD
Seagate Barracuda 500gb 7200rpm SATA
Asus Blu-Ray Burner
Corsair H100 cpu cooler (on performance mode) with 2x Feser Triebwerk TK-123 (212 CFM) fans in exhaust at top of case.
Evga GTX 580 Classified Ultra (PCI-E Slot 2)
Evga GTX 580 Classified Ultra (PCI-E Slot 5)
OCZ ZX Series 1000W PSU (mounted to exhaust out the bottom of the case)
CoolerMaster HAF X Case (positive pressure)
Modified side panel - replaced plexi-glass window with aluminum mesh
Side Panel 200mm intake @ 110cfm
Side Panel 120mm intake @ 96cfm
Front 230mm intake @ 110cfm
Rear 140mm intake @ 60cfm
Front 140mm intake @ 60cfm

120mm GPU fan @ 96cfm - blows directly between the gpu from the rear, along the cards. (If you know the HAF X you know what GPU duct I used)
All fans are linked to controller(s), for what its worth.

Ambient temperature is around 23C

Using most recent 295 drivers

Now, the problem is that GPU1 is currently idling at 24C while GPU2 is currently idling at 39C.
I setup a custom fan profile in Precision that starts at 40C and 40% fanspeed.. and increases linearly to 100% at 90C
Under load with stress test GPU1 reaches 61C and GPU2 reaches 64C.
With BF3 on ultra GP1 reaches 55C and GPU2 reaches 57C.

The load temperatures dont bother me whatsoever, in fact I am quite pleased. However the idle temperatures bug me a great deal.

Any help? Thoughts? Advice?

Thanks in advance!

TL;DR: My 2 GTX 580 Classified Ultra in SLI have very different idle temps (Delta 15C) and I want to know why.

The answer is actually pretty simple (I'm assuming). Even though your PSU exhausts out the bottom, some air blows back in and you get ambient heat withing the unit itself. Your PSU temps probably don't change that much overtime since it's a 1000 watt PSU. The excess heat from the PSU leaches into your bottom card because, well, heat rises.

Another possibility is heat getting trapped between the two cards. Card 2 lets heat out of it's back-plate and Card 1 blows both it's hot air and the air coming from Card 2, back towards card 2.

The answer to this is: SLI causes card two to get hot. My friends' rigs get hot, when I had a second 560 that card got hotter than the one on top. It really is not a big deal. If your cards were reference they would have even higher temps on idle. Don't worry about it.

 

[superjonesy]

Best answer selected by SuperJonesy.