RTX 4090 on PCIe 1.1

[G-ZooM]

Hello!

 

I built a new PC two weeks ago when Ryzen 7 7700X launched and now have a Gigabyte RTX 4090 gaming OC hiding my whole motherboard. Upgraded from R7 2700X + GTX 1070.

After 2 days of gaming, I opened GPU-Z 2.50.0 this morning and discovered that I was actually running on a PCIe 1.1 x16 bus. (HWiNFO64 7.30 confirmed it)

 

I first thought it was Windows playing the good old idle trick so I tried the render test of GPU-Z and also started a benchmark but it's still stuck at PCIe 1. I then forced the bus to PCIe 5.0 instead of 'auto' in the Bios, still nothing on Windows. Any ideas?

 

The RTX 4090 is probably not that much bottle-necked by PCIe lanes in games, but the main purpose of my system is software engineering and the project I am working on would greatly benefit from the bandwidth, especially with 24GB of VRAM! (4GB/s vs. 31.5GB/s theoretically)

It's not my first rodeo but I'm stuck with this issue.

 

Thank you in advance for your time

 

Full specs:

Asus TUF Gaming X670E-Plus

Ryzen 7 7700X

2x 32GB DDR5 5600Mhz CL40 (EXPO)

2x 2TB Kingston NVMe SSD PCIe 4.0

Gigabyte RTX 4090 Gaming OC (Power limit @70% / 315W)

Windows 11 Pro 22H2 22621.674

more: https://pcpartpicker.com/list/G9MRMb

[Eigenvektor]

Here's the benchmark for that, just for you:

https://www.techpowerup.com/review/nvidia-geforce-rtx-4090-pci-express-scaling/

 

~edit: Try putting some load on the GPU, see if the bus speeds up. Try pressing the question mark next to the bus interface.

[G-ZooM]

3 minutes ago, Eigenvektor said:

Here's the benchmark for that, just for you:

https://www.techpowerup.com/review/nvidia-geforce-rtx-4090-pci-express-scaling/

 

Oh thank you! Based on their results I wouldn't mind PCIe 2.0 or 3.0 bandwidths, but 1.1 is 20% lower overall in gaming.

[Eigenvektor]

Just now, G-ZooM said:

Oh thank you! Based on their results I wouldn't mind PCIe 2.0 or 3.0 bandwidths, but 1.1 is 20% lower overall in gaming.

Try pressing the ? next to the bus interface, it should put load on the bus to get it running at max speed.

[GuiltySpark_]

3 minutes ago, Eigenvektor said:

Try pressing the ? next to the bus interface, it should put load on the bus to get it running at max speed.

This. That's why that question mark is there @G-ZooM. It'll open a render test, just start it and you'll see the reading change.

[G-ZooM]

@Eigenvektor @GuiltySpark_
 

Already tried the render test and RDR2 benchmark and kept my eye on the Bus interface, but it didn't move. Tried again a few minutes ago on Metro Exodus, see below. The values in Hardware Monitor are odd aren't they? (315W is normal as I limited it to avoid issues with my 850W PSU until the new one arrives)

 

Edit: 105 FPS average over 3 runs @1440p Extreme + RTX Ultra, no DLSS

[G-ZooM]

Asus released a new Bios (version 0805) for my motherboard which should "Improve GPU compatibility for GeForce RTX 40 series". I don't really know if that would solve that issue but it's in Beta version so I'm not really confident in using it...

 

I will try another GPU tomorrow to see if the PCIe behavior remains the same or not. If it goes higher than 1.1, I'll update the Bios.

[GuiltySpark_]

1 minute ago, G-ZooM said:

Asus released a new Bios (version 0805) for my motherboard which should "Improve GPU compatibility for GeForce RTX 40 series". I don't really know if that would solve that issue but it's in Beta version so I'm not really confident in using it...

 

I will try another GPU tomorrow to see if the PCIe behavior remains the same or not. If it goes higher than 1.1, I'll update the Bios.

The changes in that BIOS are being released to all the OEM's. I'm running it just fine on my X670E Taichi.

[GuiltySpark_]

In fact its being talked about online right now.

 

https://twitter.com/HardwareUnboxed/status/1581431826379198466?s=20&t=Cx05EXSRfs_iOH73fTOVig

[G-ZooM]

@GuiltySpark_ It worked! Thank you so much for reassuring me regarding that beta update

 

On Windows it shifts between 1.1 et 2.0 if I start using hardware accelerated apps. As soon as I start the render test it goes to 5.0 as intended!

I will downgrade it to 4.0 as it's probably useless to have more than the card needs.

 

This Bios even fixed a few other issues I had with AM5 such as Eco mode not working and also not being able to display the Bios UI on the PCIe GPU. I always had to plug the second input to the motherboard.

 

Now, back to Ryzen Master again...

Thanks to both of you! @GuiltySpark_ @Eigenvektor

[guigamuck]

This is happening with my rig after updating the BIOS of my MSI X670E Carbon to the latest release that included AMD's AGESA 1.0.0.7a.

When the problem happens I need to reboot the machine several times in order to work at 4.0 and yes, I've tested forcing gen4 on BIOS yet the machine seems to overrule or ignore the command.

[RugaCH]

On 6/4/2023 at 3:12 PM, guigamuck said:

This is happening with my rig after updating the BIOS of my MSI X670E Carbon to the latest release that included AMD's AGESA 1.0.0.7a.

When the problem happens I need to reboot the machine several times in order to work at 4.0 and yes, I've tested forcing gen4 on BIOS yet the machine seems to overrule or ignore the command.

It's being discussed here too:

https://forum-en.msi.com/index.php?threads/nvidia-4090-gpu-stuck-at-pcie1-1x16.387014/