Question The PCIe x16 slot on my mobo is gen 4 but it's showing as gen 5 in the BIOS and CPUZ ?

[Barry_4]

I upgraded my GPU to 9070 XT (a PCIE5 card), but pretty sure my MOBO only supports PCIE4: https://www.gigabyte.com/Motherboard/B650-GAMING-X-AX-V2-rev-1x/sp#sp

CPUZ shows the graphic interface as PCIE5, 32 GT/s.

Shouldn't the GPU run at PCIE4 speed? I'm asking because the GPU is exhibiting some instabilities, and I'm wondering whether it is due to this discrepancy. Ever since I installed the new GPU, the system randomly freezes when doing nothing or freezes when waking from sleep.

However, I've stress tested in benchmarks and games, and it's never crashed in those demanding scenarios. It probably has something to do with management of power states. I've tried a clean install of the driver with DDU etc and that didn't help. I will update the BIOS to the latest released version and see if that helps.

 

[SkyNetRising]

Shouldn't the GPU run at PCIE4 speed? I'm asking because the GPU is exhibiting some instabilities, and I'm wondering whether it is due to this discrepancy. Ever since I installed the new GPU, the system randomly freezes when doing nothing or freezes when waking from sleep.

Check BIOS settings.
Try forcing PCIE slot into PCIE 4.0 mode.

What cpu are you using?
7000 and 9000 series cpus support PCIE 5.0 mode. 8000 series cpus support up to PCIE 4.0 mode.

Can you show a screenshot from GPU-Z?
(upload to imgur..com and post link)

 

[wcbhkids]

I have a 9700x. The GPU slot PCIE gen depends on CPU? Isn't it also set by the motherboard?

It won't let me insert images for some reason. Let me know if these works:
CPUZ
BIOS

Under Prom21 chipset settings, I changed PCIE Port 3 (I guess this is the port for the GPU because it's the only one that says "enabled") from auto to Gen 4. CPUZ still says Gen 5.

I've flashed BIOS to F32 the latest released version.

 

[SkyNetRising]

I have a 9700x. The GPU slot PCIE gen depends on CPU? Isn't it also set by the motherboard?

CPU supports PCIE 5.0. Motherboard is validated for PCIE 4.0 operation.
Since your graphics card is PCIE 5.0 and cpu supports PCIE 5.0,
they may be trying PCIE 5.0 mode instead and not able to auto negotiate to work in PCIE 4.0.
Then you have to force PCIE 4.0 mode manually.

It won't let me insert images for some reason. Let me know if these works:
CPUZ
BIOS

Please show screenshot from GPU-Z (not CPU-Z).

Under Prom21 chipset settings, I changed PCIE Port 3 (I guess this is the port for the GPU because it's the only one that says "enabled") from auto to Gen 4. CPUZ still says Gen 5.

Not sure, what Prom21 is.
Look in Settings/Miscellaneous/PCIE x16 Link Speed

 

[wcbhkids]

Updated BIOS to F32 (latest) and set PCIEx16 speed to Gen 4 . I will see what happens.

BIOS

Based on what I'm seeing in BIOS, it looks like this MOBO does support PCIE Gen 5 (otherwise BIOS wouldn't show Gen 5 as an option). This is odd, given Gigabyte's spec page says:

1 x PCI Express x16 slot (PCIEX16), integrated in the CPU:

1. AMD Ryzen™ 7000 Series Processors/ Ryzen™ 9000 Series Processors support PCIe 4.0 x16 mode
2. AMD Ryzen™ 8000 Series-Phoenix 1 Processors support PCIe 4.0 x8 mode
3. AMD Ryzen™ 8000 Series-Phoenix 2 Processors support PCIe 4.0 x4 mode
   * The PCIEX16 slot can only support a graphics card or an NVMe SSD. If only one graphics card is to be installed, be sure to install it in the PCIEX16 slot.

 

[SkyNetRising]

Based on what I'm seeing in BIOS, it looks like this MOBO does support PCIE Gen 5
(otherwise BIOS wouldn't show Gen 5 as an option).
This is odd

Motherboard is validated for PCIE 4.0 mode.
When motherboard was manufactured, there were no PCIE 5.0 graphics cards available.
PCIE 5.0 is available with your cpu and graphics card combination. But you may experience issues.

 

[wcbhkids]

Motherboard is validated for PCIE 4.0 mode.
When motherboard was manufactured, there were no PCIE 5.0 graphics cards available.
PCIE 5.0 is available with your cpu and graphics card combination. But you may experience issues.

So the mobo doesn't need different hardware components to support PCIE5 vs 4, and if the combination of CPU + GPU supports gen 5, the mobo will also (technically) support gen 5? That's good to know.

 

[SkyNetRising]

So the mobo doesn't need different hardware components to support PCIE5 vs 4,
and if the combination of CPU + GPU supports gen 5, the mobo will also (technically) support gen 5?

Motherboard just houses traces from PCIE slot to cpu.
It's basically a direct connection. Not much hardware between them.

But there are significant differences between PCIE 4.0 signalling and PCIE 5.0 signalling.
So - traces that are designed for PCIE 4.0 may introduce signal errors, when working in PCIE 5.0 mode.