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NVidia GTX980 SLI Question

elohim3
Level 7
Hi all,
I have recently added a second Nvidia GTX 980 to my rig to give SLI a go. I have noticed that the motherboard is not allowing it to use a x16/x16 setup, and says it is running in x16/x8. If I look in the GPU post section of the Tool menu, it shows the card in PCIE_X16_1 linked at x16 Native, and the card in PCIE_X16/X8_3 linked at x8 Native.

I am running an Intel 5930k so I know I have 40 lanes to work with (also updated to 1801 BIOS just to make sure it wasnt that). Is there something I'm missing here that is preventing the second card from seeing all 16 lanes? (and yes, I know at PCI3.0 x16/x16 vs x16/x8 is supposed to be the same performance wise, but still... 😉 )
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21 REPLIES 21

Menthol, the cards are both in the x16 slots (1 and 4 on that image you linked).

I am going to pull them out and then run them each alone and will get back to you guys. If they both run at x16 in the main slot, I will try to force 3.0 through the bios to see if that changes anything.

Also, heat isn't an issue for my build - between the Corsair H110 and the massive 900D case with fans, the cards have plenty of space to dissipate heat 🙂

So after some testing, I'm still stuck. Either card in slot 1 alone will run at x16. If I add a card to the x16/x8_3 slot, it only runs at x8. On a hunch, I put just one card in x16/x8_3 and left x16_1 empty. The system is still only utilizing the x16/x8_3 slot as x8 and not x16. I put the entire system back together and tried to force Gen3 like Pleot had mentioned. This also made no difference. At this point, I'm stumped!

MatG
Level 9
You can only get x16 on both cards if you got a Core i7-5960 cpu.
5820 and 5630 only works with x16/x8 in SLI.

MatG wrote:
You can only get x16 on both cards if you got a Core i7-5960 cpu.
5820 and 5630 only works with x16/x8 in SLI.


Incorrect. Well, correct about the 5820 because it only has 28 lanes. But the 5930k has 40 lanes, and I have two 980 TI's in 16x (confirmed), as well as a PCIe NVME Intel 750.

Qwinn wrote:
Incorrect. Well, correct about the 5820 because it only has 28 lanes. But the 5930k has 40 lanes, and I have two 980 TI's in 16x (confirmed), as well as a PCIe NVME Intel 750.


My fault, have just read the manual again.. Sorry 🙂

_TRG__Kicker
Level 7
I kind of read threw the posts here. Sorry if missed this and tried. Do you have the 4 pin molex at the bottom of the board plugged in to power?

Qwinn/MatG - Yeah, its the main reason I selected this proc to base my machine on because I did plan on eventually running dual or triple 980s or Titans once I had the money saved up.


Kicker - Yes, I do have that connected. I have always been of mind that a power connection should be populated if possible unless specifically told not to populate it...more available power sources is always better then not enough when running any kind of oc 😉

Qwinn
Level 11
My bad on the PCIe/M.2 issue. Didn't realize 4 lanes in that slot could still share. Sorry Hawkstorm.

elohim3
Level 7
No worries, Qwinn. When I first started looking at this issue, I had to go double check the manual again to make sure that the M.2 shouldn't effect the x16/x8_3 slot.

Still confused on what is eating those other lanes on that second x16 slot. I'm really hoping I don't have to pull this entire rig apart, put it back on the bench, and go through each component one by one to find the issue...

elohim3 wrote:
No worries, Qwinn. When I first started looking at this issue, I had to go double check the manual again to make sure that the M.2 shouldn't effect the x16/x8_3 slot.

Still confused on what is eating those other lanes on that second x16 slot. I'm really hoping I don't have to pull this entire rig apart, put it back on the bench, and go through each component one by one to find the issue...


Exact the same problem here. with new Bios 1902 Intel 5930K , same position of two 980GTX in SLI, the lower card working x8. Also i dont have M2 installed but PCI Intel 750NVMe. trying to remove Sound card / Intel750, the 2nd card working only x8.