Cannot enable SLI on Gigabyte Z97X-UD5H

[Imacflier]

Motherboard: Gigabyte Z97X-UD5H
Processor: I5-4670K, no overclock
GPU x2: ASUS GTX660-DC2O-2GD5
Power supply: Corsair AX750

First GPU is installed in PCIEx16 slot
Second GPU is installed in PCIEx8 slot
Nothing installed in PCIEx4 slot

Both GPU's appear in device manager as working properly. Both have the same driver.

Problem: "Maximize Performance" (enable SLI) does NOT appear as a choice in NVIDIA Control Panel.

In chat with NVIDIA tech, we checked System Properties in the NVIDIA Control Panel. The PCIEx16 slot appears to be running at x8 (as expected from the MB manual), but the PCIEx8 slot is running at x4. NO SLI is possible with different PCIE slot speeds.

I cannot find either in the manual or in wandering through the bios any way to correct the speed on the PCIEx8 slot.

HELP!

TIA,
Larry

 

[HEXiT]

have you connected the sli bridge

 

[Imacflier]

Yes, I have connected the SLI bridge. I also exchanged the positions of the two GPU's.

Thanks for the idea....the most obvious failure is the one most likely for me to commit!

Larry

 

[chenw]

Edit: actually, nevermind, I just saw your OP, and saw you have two 660's.

Not entirely sure what else could go wrong here, Did you install the two GPUs in the top and middle Long PCI-E lanes?

 

[HEXiT]

the only thing i can think of is your nvidia panel. open it and go to sli properties and there should be a check box .
also both pci-e slots should be working at x8 not x8 and x4
as that motherboard supports x8x8 for sli and 8x4x4 for crossfire.
so make sure you have both cards plugged in to the top most pci-e slots.
go into bios and set peg 1 mode to find the gpu on slot 1.
boot and open the nvidia panel and enable sli . that should be all you need assuming your drivers are up to date.

 

[Imacflier]

HEXit,

There are NO SLI selections available in NVIDIA Control Panel. According to NVIDIA tech support the Control Panel does not even offer the choice if the PCIE slots are operating at different rates.

Are you aware of any way to set the rate of a specific slot? I have not found any way so far. Unless there is some way, I must suspect I have a bad motherboard.

In your answer you say to "go into bios and set peg 1 mode" Is peg 1 mode setting which card to run post on? If so it is set to GTX 660 (1).

Thanks much,
Larry

 

[Imacflier]

ARRRGHHHH!!!

After removing one of the GPU's to uncover the MB serial number, and rebooting.....the problem simply went away and I got a popup telling me SLI was available!! All works now....I sure hope it does not reappear the next time I reboot!

Many thanks to all who contributed.

Larry

 

[HEXiT]

saving and quiting bios likely fixed it. as it gives the o.s a chance to refresh and verify the dmi pool data.