PCIe Lanes Harder than Rocket Science?

[nv_xmp]

Specs;
Samsung 970 EVO Plus NVMe® M.2 SSD 1TB- https://www.samsung.com/us/computin...ssd-970-evo-plus-nvme-m-2-1-tb-mz-v7s1t0b-am/

Intel Core i9-9900k Processor- https://ark.intel.com/content/www/u...9900k-processor-16m-cache-up-to-5-00-ghz.html

Asus Rog Maximus Hero XI (Wi-Fi)- https://dlcdnets.asus.com/pub/ASUS/...14808_ROG_MAXIMUS_XI_HERO_WI-FI_UM_V2_WEB.pdf

MSI Nvidia GeForce RTX 3080 Ventus 3X 10G OC - https://us.msi.com/Graphics-Card/GeForce-RTX-3080-VENTUS-3X-10G-OC

G.Skill 32GB DDR4 Trident Z Royal 3200MHz- https://gskill.com/product/165/299/...DDR4-3200MHz-CL16-18-18-38-1.35V32GB-(2x16GB)

Corsair RMx Series RM1000x 1000w 80 Plus Gold- https://www.corsair.com/us/en/Categ...ply-Units-Advanced/RMx-Series/p/CP-9020094-NA

I know what you're all thinking, another PCIe lane question I've seen this a million times over. Well, here's another one for you.

So, this is my first build and I took on the challenge because I thought I was smarter than a computer. That turned out wrong. I got everything up and running and was just doing checks to see if everything looks the way it is suppose to, and I noticed in my bios my GPU was running 3.0 x8, I believed having the GPU in the first 3.0 x16 slot would get all the bandwidth, so off I go on the google search rabbit hole and try most of the troubleshooting recommended. Re-seat GPU , Clean the pins, DDU to clean install drivers, update to latest BIOS, move m.2 SSD around to a different slot. Nothing. So I am at a loss, PC world has got me in a corner and I can't get back up. But I will prevail, even if it means upgrading to a better board...

 

[TheLostSwede]

Did you try using this in Windows while putting some 3D load on the card? Most modern graphics cards shift down to a slower PCIe spec or reduced lane width when not loaded. This is done to reduce power draw.

TechPowerUp GPU-Z v2.60.0 Download

GPU-Z is a lightweight utility designed to give you all information about your video card and GPU.

www.techpowerup.com

If you hit the question mark by the Bus Interface information, it should allow you to load the GPU sufficiently.

 

[rtwjunkie]

Your user manual doesn’t tell you which slots use which PCIe lanes? I’m think that the M.2 slot you are using has 8 of them. Is there another M.2 slot? Let me see if I can find your manual online.

EDIT: I see you have another M.2 slot. Try your SSD in that one? I didn’t ask you about GPU load because you checked in BIOS and that will show how many lanes are operational always.

 

[nv_xmp]

GPU-z result. And this is what it says from my motherboard manual. I am running the one SSD on M.2_1 Socket, no other SSD that could take up lanes.

 

[rtwjunkie]

Are you using the PCIe*16_2 slot for anything? That will reduce the first slot to x8.

 

[nv_xmp]

No, the only thing plugged in to any physical PCIe slot is the GPU in 16_1.

 

[Mussels]

reseat the GPU and blow any dust out of the slot

 

[toilet pepper]

This seems odd. I suggest that you reseat the cpu. Not the cooler. The whole cpu itself. There might be some pins on the board not making the right contact with the cpu. If that still fails. Do a bios update.

 

[GerKNG]

i actually found a few other threads on different websites with the same problem. (Asus ROG Forum for example)


neither of them were able to fix it except with an RMA.
the replacement board was fine afterwards.

 

[newtekie1]

Do you have a different card you can try? This will help narrow down if the problem is the card or the computer.

Most modern graphics cards shift down to a slower PCIe spec or reduced lane width when not loaded.

No modern graphics card reduces the number of PCI-E lanes as a power saving feature.

 

[kayjay010101]

No modern graphics card reduces the number of PCI-E lanes as a power saving feature.

That is incorrect. All modern cards (including my 3090) do set their speed to PCIe 1.1 and reduce the lane bandwidth to x1 to reduce idle power use.
But yeah, TheLostSwede is a bit off by thinking the GPU being at regular PCIe gen 3 x8 is a power-saving feature.

If I had to guess I would say the pins aren't making proper contact so the card auto-negotiates to an x8 link. This could be either a motherboard or GPU issue. As newtekie1 mentions, try another GPU or another motherboard and check the result.

 

[TheLostSwede]

It might not be the case here, but yeah...

 

[Mussels]

That is incorrect. All modern cards (including my 3090) do set their speed to PCIe 1.1 and reduce the lane bandwidth to x1 to reduce idle power use.
But yeah, TheLostSwede is a bit off by thinking the GPU being at regular PCIe gen 3 x8 is a power-saving feature.

If I had to guess I would say the pins aren't making proper contact so the card auto-negotiates to an x8 link. This could be either a motherboard or GPU issue. As newtekie1 mentions, try another GPU or another motherboard and check the result.

no they dont, they drop to 1.1 16x

 

[newtekie1]

That is incorrect. All modern cards (including my 3090) do set their speed to PCIe 1.1 and reduce the lane bandwidth to x1 to reduce idle power use.

No it is correct, no modern graphics card changed the number of lanes, they only change the PCI-E speed, not number of lanes.

 

[TheLostSwede]

no they dont, they drop to 1.1 16x

Read my screenshot above...
It can do either/or and most likely both.
But it seems like it isn't the problem the OP is having.

 

[newtekie1]

Read my screenshot above...
It can do either/or and most likely both.
But it seems like it isn't the problem the OP is having.

No, it isn't either or both. The PCI-E spec doesn't even allow this to happen. The link width is set at POST and does not change, there is not a mechanism in PCI-E that allows on the fly PCI-E link width changes. The only thing close to that is ASPM. That however is an on or off only system. Allowing the PCI-E slot to be completely off or on, or off/on in one direction. When it comes to graphics cards, this is used in laptops to disable the dGPU. On desktop, it was used by AMD in a few rare configuration with Crossfire enabled to disable the second GPU when there is no 3D load. But the link width never changes. ASPM is likely what GPU-Z is referencing as cards that are disabled with ASPM will usually show as having a x0 link. So stop suggesting it does in threads like this, it just wastes time.

If you disagree, find me just one thread where loading the card changed the number of PCI-E lanes and fixed this issue. You just have to show one single example.

 

[Mussels]

Read my screenshot above...
It can do either/or and most likely both.
But it seems like it isn't the problem the OP is having.

no swede, the number of lanes doesnt change. Only the generation does.

GPU-Z has that fade that makes it hard to screenshot, but i literally did show it with my 3090 to counter your claim

 

[Caring1]

Change the PEG/Port config from auto to your desired speed X16.
Your CPU has a maximum of 16 lanes and with the NVME taking up 4 of those it might not automatically select the chipset lanes for that drive, instead sharing CPU lanes.

 

[nv_xmp]

This is the only option for PEG, And im curious as to why the x16_2 is there almost as if being used by something..?
I will reseat my CPU and check for any pins that could have been damaged later today and will see if this solves it.

Also, is my PCH temps high for just being the bios?

 

[newtekie1]

And im curious as to why the x16_2 is there almost as if being used by something..?

It always shows, but it says "Not Present" meaning nothing is plugged into the slot. You don't have options to change lane number in the BIOS.

Like I said, try a different GPU if you can, or try the GPU in a different computer. We need to narrow down if the problem is the GPU or something else in the system.

Being that it says x8 even in the BIOS, we know for sure nothing in Windows is causing the problem. So there is no use in focusing on solutions there.

 

[nv_xmp]

I have an older 1030 card I can try tonight.