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SLI X2 PCIe Problem

Last response: in Graphics & Displays
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March 27, 2012 2:21:59 PM

The following are my current system specs:

I7 990x CPU (Corsair H100 Liquid Cooler) running at 4.4 Ghz with a multiplier of X33 @ 133Mhz FSB
Intel DX58SO2 Motherboard
Antec HCP-1200 Power supply
Kingston HyperX DDR3-1600 (24 GB) Memory
Corsair 800D Case
Two 300GB WD VelociRaptor (Raid 0) Hard drives
Win7 Pro 64bit OS
Two SLI eVGA GeForce GTX 460 1GB SC GPU’s (Not EE) (OC’ed 850 / 1700 / 1900)
Asus Xonar DX Sound Card

I had been running my videocards in the top two PCIe slots with no trouble in SLI mode. However, the top card gets very hot, not so hot that the gpu throttles, but close. This heat issue is the result of the cards being to close together. The cards are literally millimeters apart…

So, I bought a 120mm SLI link, and moved my bottom card to the third PCIe slot. (Skipping the middle slot) This created space between the cards, which I expected would dramatically assist in heat management.

So, I plugged my rig back in, and once booted up, note that I can only see one v-card… I go to BIOS, and the third PCI’e slot is showing that it’s not populated, and I cannot see any place in the BIOS where I can force it to recognize that there is a v-card in the 3rd/bottom PCIe slot. I flashed the BIOS using the boot method, no change…..

So, to make a long story short; I ended up contacting Intel support and spoke with a very nice man who spoke fluent, but extremely difficult to understand English. I asked him, “how do I get the bottom PCIe slot on my MOBO to recognize it has a v-card in it? After a long an arduous conversation he finally tells me…. “I don’t know”. He referred me to this diagram at http://ark.intel.com/products/52585#blockdiagrams and alluded that the issue may have something to do with the PCIe controllers on the IOH and ICH hubs of my processor not talking with each other, or possibly the 3rd PCIe slot on my MOBO is connected to the IOH hub, while the top two slots are connected to the ICH hub, or vice versus. He did tell me that the issue can likely be resolved by another Intel person (could not understand the title) but that would involve me signing a confidentiality agreement with Intel!?!?!

I’m looking to run this rig in sli using the top and bottom PCIe slots on the board. Can anyone, please, explain to me how I can get the bottom PCIe slot on my MOBO to recognize a card plugged into it. I am certain there is a way, I’m just not sure what that way is?

Thanks!

More about : sli pcie problem

March 28, 2012 3:01:15 AM

Well, I suppose, if Intel support could not answer the question, it's probably not likely anyone here can... Oh well, it was worth a try.

Thanks to all that took the time to read my question!
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March 28, 2012 3:34:44 AM

Well to beigin with, the cards run pretty hot anyway; moving the cards would likely result in a marginal difference in temps.
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March 28, 2012 12:01:16 PM

Yeah, they run hot, but 75 - 80C under mild loads is to hot and temps of 99 - 105C during stress tests are just plain destructive. When I take one card out and stress test it, I get temps MUCH lower; no more than 65 - 72C... So, you're actually incorrect, allowing the cards to "breath" makes a tremendous difference in temps.
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March 28, 2012 1:47:32 PM

I saw another post like this and disabling usb 3.0 fixed it for him. Apparently on his board the usb 3.0 shared lanes with pci-e or something wierd... worth a shot.
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March 28, 2012 4:27:04 PM

lmulder said:
I saw another post like this and disabling usb 3.0 fixed it for him. Apparently on his board the usb 3.0 shared lanes with pci-e or something wierd... worth a shot.


EXCELLENT!

I had not thought of this, and in fact, I believe the DX58SO2 may have been re-engineered to include USB 3.0 during development… This sort of last minute addition can cause weird issues… (assuming my assertion is accurate)

I’ll look into it and let you know how it works out..
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March 28, 2012 10:48:14 PM

lmulder said:
I saw another post like this and disabling usb 3.0 fixed it for him. Apparently on his board the usb 3.0 shared lanes with pci-e or something wierd... worth a shot.


Well, it was a good idea, but unfortunately, disabling the USB 3 controller had no effect.

I also noted that the machine will not recognize a single gpu in the bottom slot, but it will recognize a PCIE X1 (Goldfinger) PCIE sound card while the top two slots are occupied with my two gpu's running SLI... So, I know the slot is functional... I just need to figure out how to enable it so I can skip the middle PCIE slot...

I also tried plugging in my sound card in the middle slot, and plugging in the second gpu in the bottom one. The system recognized the sound card, but not the gpu... I also noted another unpleasant detail... While all three PCIE slots are occupied with .......somthing.... The bottom two drop to 8X versus, 16X... A little research determined that this is an idiosycracy of the DX58SO2... So, even with three gpu's, you the only performance increase you'll see is less stress on the bottom two cards, there are no actuall gaming or application performance increases, running 3 cards in SLI in this MOBO, it is essentially the same as running two, in SLI, performance wise....

Word to the wise, do not buy the DX58SO2, you'll regret it!
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March 30, 2012 11:28:05 PM

I still have not found a solution, I know one does exist, but I'm drawing a blank. Anyone else have any ideas?
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April 7, 2012 12:07:30 AM

I'm getting emails suggesting that I should pick a best answer, but I have not received an answer to my inquiry.
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April 7, 2012 12:55:48 AM

If you are having trouble with heat like I did, you can always turn the case on it's side. I have an Antec 1200 and was running multiple gpus and turning the case on its side dropped the temps of the gpus. I also flipped my psu upside down so the fan was facing down. There is a lil bit of clearance there so no worries. Note, I also had a pci slot fan blowing air out. So I had multiple outlets of air. This is what I have

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
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April 7, 2012 3:36:43 PM

pharoahhalfdead said:
If you are having trouble with heat like I did, you can always turn the case on it's side. I have an Antec 1200 and was running multiple gpus and turning the case on its side dropped the temps of the gpus. I also flipped my psu upside down so the fan was facing down. There is a lil bit of clearance there so no worries. Note, I also had a pci slot fan blowing air out. So I had multiple outlets of air. This is what I have

http://www.newegg.com/Product/Product.aspx?Item=N82E168...


I like that slot fan! Unfortunately the only slot I have avalable is right below my bottom videocard. I'm not sure how much effect that will have on my top gpu temps. The Corsair 800D is extremely well ventilated, and it's huge. I don't have space enought to lay it on its side, damn thing would take up an acre... lol... As it it, it's like a darned wall next to my monitor, a wall with pretty blue lights inside. :)  Also the way the case is set up, I really can't mess with the psu positioning much, it's on the bottom of the case, in its own little enclosed area... Here check this out so you can understand what I mean: http://www.youtube.com/watch?v=4qRplm7AWWA go to the end of the video to see how the psu compartment is configured.
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April 18, 2012 10:46:01 PM

I still have not been able to resolve this issue. I've not had the time to consult with intel support, and I'm a little sketchy over having to sign a confidentiality agreement. The reason why, is I beleive that the answer to my question should be shared so others can take advantage of the solution.
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April 26, 2012 3:08:15 PM

I received an email advising I had new answers to my question, but I don't see any... I can't pick a best answer till my question is, oh I don't know..........answered?
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Best solution

April 26, 2012 4:17:10 PM

If it fixes your problem I would sign it, since they would probably have you talk to one of Intel's engineers. You shouldn't be having an issue since there is only the ICH controller on X58 boards (to my knowledge).
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April 26, 2012 5:24:28 PM

X58 boards have both a northbridge and southbridge (IOH and ICH respectively) while P67 boards only have one chip (still called the PCH platform controller hub?).
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April 26, 2012 6:00:34 PM

Ah yes, the ICH10R, I had forgotten about that. Still, it's a rather strange issue to have, although I know on mine if I place the card in the bottom slot with none in the stop I get the 30 min slow boot issue. I'm sure it has to do with the architecture of how they mapped the PCI-e slots, although the only lanes that should be attatched to the ICH are the x1 lanes.

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September 4, 2012 3:37:28 AM

Best answer selected by Bacon12.
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