PCI-E runs at x8 instead of x16

[Brazen_]

Question... Just noticed my Gigabyte GTX 1070 G1 PCIe_x16 adapter is only running at x4 on PCIex16_1 slot One! I have only one drive installed which is a PCIe_x4 NVMe 3.0 stick in slot M.2_1. According to everything I've read, including the manual, M.2_1 should NOT affect PCIex16_1. Since it's my boot drive, I can't (not do I want to!) pull the NVMe drive to see if the video adapter jumps to it's default x16 mode. Both the BIOS and GPU-Z report the current x4 bandwidth. BIOS doesn't even list the PCIex16_1 to adjust settings. The other 2 slots are present, w/optional settings. It's an 8/16 core Ryzen 7 2700x so I can't see the CPU lanes as a limiting factor?

I found an "Intel i5" post that suggested it could be the sound circuitry built into the GTX adapter "and" Motherboard hogging up lanes, but found no help on the Ryzen 7. This is a new build and my first Ryzen so I'm learning as I go. Any thoughts?


AMD Ryzen 7 2700x
Asus ROG STRIX x470-F
16gb G.Skill TridentZ RGB (2x8)
Gigabyte 1070 GTX G1 Gaming 8gb
Intel 660p M.2 nVME 3.0 1024GB
Corsair tx850w PSU

https://www.newegg.com/intel-660p-se...82E16820167462

https://www.gigabyte.com/us/Graphics...-8GD-rev-10#kf

[_H0PE_]

I've noticed while mucking around in BIOS last few days that my PCIE16x_1 primary slot with my rtx 2080 is on x8 speed.
At the time I only had two m.2 in the slots and no other devices connected to the mobo (other than cpu of course).
Is this normal behavior or I should see x16 for the slot?
Tuf Z370-pro gaming motherboard.

[Sathorn]

found a solution, posted there https://rog.asus.com/forum/showthrea...245#post813245

[BB_Deluxe]

I realize this thread isn't for my mobo but appreciate the troubleshooting advice given and I'm happy some of you figured out a solution. Unfortunately, this issue is still affecting my X99 Deluxe ii motherboard with a new 3090 card. I tried to reduce bandwidth for all other PCI-E slots as well as use every auto combination method available and still no dice on PCI-E_1. It maxes out at x8. I have to use slot 3 for x16 speed.

My details were posted here ( 1070 now a 3090 ): https://rog.asus.com/forum/showthrea...-CPU-x8-native

[nonspin]

Even though it's a bit late, let me point out one little detail.. The difference between 8x and 16x is not noticeable. It certainly isn't "TWICE AS"-something.
Secondly .. and this is an experience thing .. and you can try it youself:
If you tighten the screw(s) (gpu) just a little bit too much, it'll change to 4x .. 8x .. 2x .. like a lottery.

[Wangeyed]

Even though it's a bit late, let me point out one little detail.. The difference between 8x and 16x is not noticeable. It certainly isn't "TWICE AS"-something.
Secondly .. and this is an experience thing .. and you can try it youself:
If you tighten the screw(s) (gpu) just a little bit too much, it'll change to 4x .. 8x .. 2x .. like a lottery.

how tight your gpu is screwed in does not effect anything, i fixed this by removing the bios bat, clearing cmos jumpers didnt work.

[Stormwind81]

So this thread is a mess like no other.
I have an Rog Strix X299-E and having the same issue with a new 3080Ti.
It only shows x8 when it should 16x.
I have installed it via an riser cable that even supports PCIe x4.0 and my vendor is now asking me to send the cable back cause they dont have any idea either.

People reported they
a) put card in a different slot (reseating)
b) reseted bios
c) changed whole Motherboard

I am still not sure but at home I will try to reseat my GPU too.
In the bios it only shows x8 no matter what I try.
And I have 2 NVMe SSDs installed but why should they matter?

[Stormwind81]

Update:
I put my GPU from slot1 to slot2 of my PCIex16 and now it is showing x16 again.
Dont ask me why but it worked.

[thunderrd]

Update:
I put my GPU from slot1 to slot2 of my PCIex16 and now it is showing x16 again.
Dont ask me why but it worked.

Now you should try placing it back in slot 1, and see if it works there now.

I have found, almost without exception, that this issue is a result of poor/incomplete physical contact in the PCIex slots. Using a good-quality contact cleaner on both the GPU insertion tab and in the slot itself, I have nearly always been able to solve the problem [especially when I know that the card worked at x16 previously.]

Look for any warpage on the insertion tab itself, or any dirt/corrosion on the contact areas of the card and the slot. Sometimes it takes a little perseverance, and reseating the card in/out several times. On heavy GPUs, look for sagging of the card after insertion, and if it sags try using a small support to wedge the sagging section of the card up. I have seen this solve the problem, and have concluded that when the card sags, it loses contact in the slot.

I don't claim that this will solve the problem every time, but I've see it on at least 20 different computers and in every case but one I solved the issue this way.