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Rampage V Edition 10 PCIE Question

dlwilliams
Level 7
Hoping for some insight.

I am using Rampage V Edition 10 with 6800k, GTX 1080 and Intel 750 U.2 SSD.

When I enable the U.2 SSD, the bandwidth of PCIE Slot 1 is limited to x8 instead of running at full x16. It seems to me that I should have plenty of lanes / bandwidth to cover everything I am running at full speed.
Is this common with x99? Is this something that can be fixed? I've spoken to support who have said that I am out of luck. Any insight would be appreciated.

I can run all components at full speed on a $250 z170 board. Hoping there is a way for this $600 board to do the same.

THanks
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37 REPLIES 37

erix_jansen
Level 7
I am running Intel SSD PCIE 750 and GTX980TI STRIX together at full speed on a Asus X99-S, so you WILL be able to run it : ) I believe you call that PCI slot as "slot 1" wrongly....

My 750 is u.2 not pcie. When I say slot 1, I am saying the first slot directly under the CPU. If I was using a pcie 750, there wouldn't be an issue here. It is how the board handles enabling the u.2 port that is lowering the bandwidth to x8.

The other interesting thing is on my X99-E WS, I can get full bandwidth for everything by using the asus hyper kit. It seems to be the inclusion of both a u.2 and m.2 port that is causing the underline issue.

dlwilliams wrote:
My 750 is u.2 not pcie. When I say slot 1, I am saying the first slot directly under the CPU. If I was using a pcie 750, there wouldn't be an issue here. It is how the board handles enabling the u.2 port that is lowering the bandwidth to x8.


Correct.

Are you using GPU-Z to check that it's running at x8? If so, have you tried running the render test or a GPU intensive program like Furmark to see if the GPU goes back up to x16?

Chino wrote:
Correct.

Are you using GPU-Z to check that it's running at x8? If so, have you tried running the render test or a GPU intensive program like Furmark to see if the GPU goes back up to x16?


Yes, I am using GPU-Z during heavy activity to verify the link speed. I believe the cause of this is due to the x8 bandwidth being used when I enable the u.2 port. My other board does not have an m.2 and u.2 port, so the most bandwidth that is enabled is x4. I know it can be done how I am expecting on x99, it is just the way this board specifically was designed that is causing this issue. Maybe they can fix with a bios update.

erix_jansen
Level 7
ok, i wanted to say that the real Slot 1 is unaffected by M2 or U2, the slots that reduce speeds are at the bottom... There must be a BIOS option to disable U2/M2 totally.

erix_jansen@hotmail.com wrote:
ok, i wanted to say that the real Slot 1 is unaffected by M2 or U2, the slots that reduce speeds are at the bottom... There must be a BIOS option to disable U2/M2 totally.


The point is I do not want to disable them. I need the u.2 port.

Menthol
Level 14
Not having your board or CPU the manual says
the M.2 and U.2 ports share bandwidth with PCIEX8_4 slot, a 28 lane CPU in 2 or 3 way sli will disable the U.2 port
If you only have one GPU and no other pcie cards installed I would think your GPU would operate at X16

Is this showing x8 in the bios, have you tested while under load in Windows to verify if it is only operating at x8 mode, if it operates at x16 in Windows I wouldn't worry about it

And yes a Z-170 boards PCH has 20 pcie 3.0 lanes where X-99 only has pcie 2.0 lanes so a M.2 or U.2 3.0 x4 drive can use lanes from the PCH on Z-170, on X-99 it has to use lanes from the CPU there is no way for ASUS to change that