Question I can't find the PCI_E3 Gen Setting in BIOS ?

[AlexST]

Hi everyone,

I just built a PC with a MSI MPG Z790 EDGE WIFI DDR4 motherboard and I'm struggling to find the BIOS Gen setting for PCI_E3.

As per the manual:

2x PCIe x16 slots:

• PCI_E1 slot (From CPU)
  Supports up to PCIe 5.0 x16
• PCI_E3 slot (From Z790 Chipset)
  Supports up to PCIe 4.0 x4

https://download.msi.com/archive/mnu_exe/mb/MPGZ790EDGEWIFIDDR4.pdf

I installed my secondary GPU (NVIDIA T600 PCIe 3.0 x16) into PCI_E3 and I expect it to run at PCIe 3.0 x4 in the 4.0 x4 slot.
However, it gets assigned Gen1 and therefore runs at 1.0 x4.

I can only find a PCIe Generation setting in the BIOS for the PCI_E1 which is not what I need - as that slot behaves correctly with my main GPU (which is PCIe 4.0 x8).

I don't have any M2 drives installed, therefor didn't touch the settings for those. I can't find any piece of text in the docs that implies that any of those M2 Gen settings would affect the PCI_E3 Gen setting anyways.

Can I get some advice on this please?

Thank you.

 

[Colif]

where is it showing its only PCIe 1.0? GPU-Z?

It could be the nvidia drivers to blame - https://www.techpowerup.com/forums/...but-the-second-gpu-running-at-pcie-1x.292413/

 

[SkyNetRising]

I installed my secondary GPU (NVIDIA T600 PCIe 3.0 x16) into PCI_E3 and I expect it to run at PCIe 3.0 x4 in the 4.0 x4 slot.
However, it gets assigned Gen1 and therefore runs at 1.0 x4.
Can I get some advice on this please?

Put some workload on this card. It will switch into PCIE 3.0 mode.
At idle mode it will work in PCIE 1.1 mode (to save power).

 

[AlexST]

where is it showing its only PCIe 1.0? GPU-Z?

It could be the nvidia drivers to blame - https://www.techpowerup.com/forums/...but-the-second-gpu-running-at-pcie-1x.292413/

Thanks for your response.

It's showing the max/current link speed/width/etc... in the driver details tab for each display controller device.

It's showing the max settings correctly for both devices as per each card's specs. ..but shows Gen1 x4 instead of Gen3 x4 for the secondary GPU in PCI_E3 (Gen4 x4 slot).

Re: NVIDIA Drivers
Both cards were in a Maximus Formula V motherboard up until yesterday with the same NVIDIA Studio Drivers and both were maxed out correctly in the driver details page, even in idle mode.
Note I did have to go into the Maximus BIOS to enable the correct Gen for the slots for it to work as expected.

The issue is I don't find the equivalent settings on the MSI motherboard. (for PCI_E3)

 

[AlexST]

Put some workload on this card. It will switch into PCIE 3.0 mode.
At idle mode it will work in PCIE 1.1 mode (to save power).

I'll try that, but please note this wasn't the case up until yesterday with an older ASUS motherboard - I just posted some more details in another response. ...and the main GPU is also idle yet it uses the correct Gen. Doesn't really add up TBH. Thank you.

 

[SkyNetRising]

I'll try that, but please note this wasn't the case up until yesterday with an older ASUS motherboard - I just posted some more details in another response. ...and the main GPU is also idle yet it uses the correct Gen. Doesn't really add up TBH. Thank you.

On old board you probably had power saving disabled.

 

[AlexST]

On old board you probably had power saving disabled.

Thank you, that's quite possible. There are tons of tuning settings on these Z boards, I'll have to dig through all these indirect ones so in absence of a definitive per-slot PCIe Gen selector.