cancel
Showing results for 
Search instead for 
Did you mean: 

Maximus XI Extreme Dimm.2 and pci lanes

Peregrinus
Level 7
So i have a 1080ti ftw3 gpu in my pcie_1 slot
and i also use a pci 4x usb card for oculus rift. in my pcie_3 slot as i assumed this used chip set lanes?
and im using at the moment the dimm.2 card with a NVME drive as my boot drive.

for whatever reason i'm getting my gpu as x4 ( in pcie_1 slot )
and x2 or x4 both work in pci3 for the usb card, i honestly dont know if it matters either way, i think the card will work with x2? preferably to keep my sata5/6 slots.
here's a link to the card speicifially i use for usb: https://www.amazon.com/StarTech-com-Express-SuperSpeed-Dedicated-Channels/dp/B00HJZEA2S/ref=sr_1_3?i...

i thought the way i had it setup i would get to use 2 nvme drives in the dimm.2 card slots and the gpu would be x8/x8? am i wrong? is each dim slot x8? im so confused. doesnt pci slot 3 go off the chipset? only slot 1 and 2 use cpu lanes?

i have no issue with my gpu in x8 but i'd prefer it not to be in x4 mode for sure.

what can i do to remedy this?

thanks guys! if u need more info please just ask.

system:
9900k
maximus extreme XI
boot drive samsung pro 970
and a gtx t1080ti ftw3 black
custom water loop
corsair dominator pro ram 32gb
4,096 Views
9 REPLIES 9

G75rog
Level 10
The pcie slot allocations and dimm card usage are explained in your user manual.
Pciex16_1 and pciex16_2 share the 16 available cpu lanes.

Let me reiterate,

At the moment I am using PCI slot 1 for the 1080, I skipped pci2 and used slot 3 for the USB card.

So slot 2 is empty. The graphics card should be running x8 am I wrong? This is what I am not understanding.

Using dim.2 with nvme, gpu in slot 1 slot 2 empty slot 3 has USB card.

Slot 3 should run off of the PCH Lanes and not the CPU correct? Why is the gpu being limited to x4.

I also updated to 0805 bios last night hoping maybe that would help, but didn't change anything.

Peregrinus wrote:
Let me reiterate,

At the moment I am using PCI slot 1 for the 1080, I skipped pci2 and used slot 3 for the USB card.

So slot 2 is empty. The graphics card should be running x8 am I wrong? This is what I am not understanding.

Using dim.2 with nvme, gpu in slot 1 slot 2 empty slot 3 has USB card.

Slot 3 should run off of the PCH Lanes and not the CPU correct? Why is the gpu being limited to x4.

I also updated to 0805 bios last night hoping maybe that would help, but didn't change anything.


Can't tell you why it's x4. But I believe the dim.2 slot uses cpu lanes...(if that's the slot near the ram slots)

Peregrinus
Level 7
I do have the gpu going through a riser card so I can vertical mount it, I will try cleaning the cable and contacts and reseating it tonight, maybe that could be effecting something.

But as far as I can tell on paper, it "should" be running the gpu and the dimm.2 in x8/x8 mode. I don't get why I'm getting x4.

Peregrinus
Level 7
ok guys update, i reseated the gpu with the riser card.

i also took out the dimm.2 slot entirely, so at this point pcie slot 1 has my 1080ti

and slot 3 has the usb card running in x2

and im STILL getting my gpu running in x4 from gpu-z with it loaded up.


at this point am i to think that the issue is the riser card or what? it should DEF be running in at least x8 now.

Peregrinus
Level 7
update #2.

removed dimm.2 and put gpu directly in slot 1 eliminating riser card, which took me 2 hours because i had to redo my water lines.

card now runs in pci 3.0 x 16 so apparently it was the riser card. oh Well, problem solved. thanks guys!

vinceX
Level 8
Would it be possible to run the DIMM.2 slot from the PCH bus instead and disable the third PCIE slot?

Peregrinus
Level 7
I dont think so, pretty sure its tied directly to the cpu lanes.

i still want to try to get 2 ssds into the dim slots and keep my 1080 at x8, i havn't tested if this works yet.

pretty sure to use both dim slots AND keep my gpu at x8 though i have to use the second pci slot though, so to test, id have to tear apart my loop, yet again.

erixx11
Level 11
I have this working
pcie slot 1 GPU X8
pcie slot 2 empty
pcie slot 3 Intel ssd card x4
DIMM.2.1 and 2: 2 ssd (x?)
PCH ssd under cover slots: empty, too hot and terrible placement.