Problem with 1080ti SLI and PCIE m.2

[ximenji]

Dear all,

I am quite sure you can help me. I have the following set up
i7 6950x overclocked 4.3Ghz, 1.25V
Asus Rampage V edition 10
Dual SLI GTX1080 Ti on ports 1 and 3
On-Board M.2 with Samsung Pro 960 1tb
PCI-E m.2 drive (samsung 960 EVO) currently connected on port 2

Here is my problem, my second GPU is running in 8x. I tried to put the PCIE-M2 drive on port 4 but in that case, my on-board m.2 drive is no longer visible in bios.
If i remove the PCI-m2, my GPU is running in 16x.

Looking on the forum threads before installation, i understood that everything should work smoothly if i put the SLI in port 1, 3 and PCIE M.2 drive in port 4. This should be ok with 40 lanes right?

I am quite sure some expert will be able to guide me to a proper solution to my problem.

thanks

[Chino]

ximenji wrote:

Looking on the forum threads before installation, i understood that everything should work smoothly if i put the SLI in port 1, 3 and PCIE M.2 drive in port 4. This should be ok with 40 lanes right?

No, the PCIe 3.0 x8_4 slot shares bandwidth with the the M.2 and U.2 ports. Since you already have a M.2 drive installed in your M.2 port, you won't be able to install another one in the PCIe 3.0 x8_4 slot.

You'll have to decide on which route to go. Installing the M.2 SSD in the PCIe 3.0 x8_2 slot will ensure you get the maximum performance from your SSD with the compromise of running your second GPU at x8. Or install the M.2 SSD in the PCIe 2.0 x4_1 slot at which case both your GPU will operate at x16/x16, but your SSD will be limited to PCIe 2.0 performance.

[ximenji]

Thanks for your reply. I understand better now.

What will be the impact on SSD speed if connected on Pcie2x? Overall, i guess maintaining the PCIE s2 oin port 2 might be the most efficient right?

[tommiboi]

you will NOT notice any differnce on the m.2 performance ! Unless you can feel the 0.001 sec delay. 🙂
I dont even think you would noitce the differnce between a SSD and M.2 ssd.

I have m.2 in raid zero..... Just because I can. But it has no real world improvement vs a normal ssd.