PCI Express x4 slot running at x1

[archvile]

I have an Aorus Ultra Z390 board. When I plug a GPU in the x4 slot, it runs at x1. Here's what I tried:

- I have 2 GPUs, and they both run at 16x on the 16x slot, and 8x on the 8x slot. Both run 1x on the 4x slot.
- I removed everything but the CPU and RAM sticks from motherboard. No m.2 drive or anything else that shares PCI EX bandwith. Still happening.
- I reseated the CPU.
- Checked for bent pins in the CPU socket, it's a brand new mobo, everything's good. No bent pins.
- Sprayed some air into the PCI Ex 4x slot to clear any dust.

I can see the GPU running at 1x while plugged in the 4x slot in the BIOS. So it's not an OS thing.

The only thing I can think of is that, I really need to push the GPU to get it into the 4x slot to hear the lock click because part of the GPU gets on top of some mobo connectors like case front panel connectors and USB headers. Maybe too much force pushing down bent something? I don't know if that would cause a problem.

Any ideas are greatly appreciated.

 

[cucker tarlson]

I have an Aorus Ultra Z390 board. When I plug a GPU in the x4 slot, it runs at x1. Here's what I tried:

- I have 2 GPUs, and they both run at 16x on the 16x slot, and 8x on the 8x slot. Both run 1x on the 4x slot.
- I removed everything but the CPU and RAM sticks from motherboard. No m.2 drive or anything else that shares PCI EX bandwith. Still happening.
- I reseated the CPU.
- Checked for bent pins in the CPU socket, it's a brand new mobo, everything's good. No bent pins.
- Sprayed some air into the PCI Ex 4x slot to clear any dust.

I can see the GPU running at 1x while plugged in the 4x slot in the BIOS. So it's not an OS thing.

The only thing I can think of is that, I really need to push the GPU to get it into the 4x slot to hear the lock click because part of the GPU gets on top of some mobo connectors like case front panel connectors and USB headers. Maybe too much force pushing down bent something? I don't know if that would cause a problem.

Any ideas are greatly appreciated.

checked that in bios? on my gigabyte board (though much older) this has to be set manually under pci-e pch speed,I choose x1 or x4.

 

[archvile]

checked that in bios? on my gigabyte board (though much older) this has to be set manually under pci-e pch speed,I choose x1 or x4.

There's a setting to choose pci-e version as in gen1, gen2 or gen3; but I don't see a setting to change speed unfortunately.

 

[newtekie1]

Do you have an M.2 SSD plugged into the M2P slot?

 

[archvile]

Do you have an M.2 SSD plugged into the M2P slot?

- I removed everything but the CPU and RAM sticks from motherboard. No m.2 drive or anything else that shares PCI EX bandwith. Still happening.

 

[mstenholm]

For the older Asus MBs you must go to Onboard Devices Configuration in Bios to make changes for PCIex4_3. Been there?

 

[newtekie1]

I removed everything but the CPU and RAM sticks from motherboard. No m.2 drive or anything else that shares PCI EX bandwith. Still happening.

Ah, in that case I'd say it is because the GPU isn't actually making a good connection in the slot based on you needing to press so hard to get it to click in. Thost bottom slots aren't really meant for GPUs.

 

[archvile]

For the older Asus MBs you must go to Onboard Devices Configuration in Bios to make changes for PCIex4_3. Been there?

The only setting in BIOS regarding PCI EX slots is the setting where you choose gen1/gen2/gen3, which doesn't resolve my issue. There are no other settings.

Ah, in that case I'd say it is because the GPU isn't actually making a good connection in the slot based on you needing to press so hard to get it to click in. Thost bottom slots aren't really meant for GPUs.

Anything I can try to make it work?

 

[aQi]

You should take a torch see of the slot and try to look for bad pins first.

 

[newtekie1]

Anything I can try to make it work?

Try making it so you don't have to force the card into the slot.

 

[archvile]

I inserted an m.2 drive into the M2P slot, which shares bandwidth with the pci e x4 slot, and I see that the SSD is running at x1 just like the GPU in the x4 slot. So I guess it's not about the actual pci e slot. Maybe a problem with the pci bus? I think something is wrong with this motherboard.

 

[aQi]

I inserted an m.2 drive into the M2P slot, which shares bandwidth with the pci e x4 slot, and I see that the SSD is running at x1 just like the GPU in the x4 slot. So I guess it's not about the actual pci e slot. Maybe a problem with the pci bus? I think something is wrong with this motherboard.

Are you on the latest bios ?

 

[archvile]

Are you on the latest bios ?

Yes

 

[aQi]

Yes

Have you tried it with any different processor?

 

[Mussels]

From the product page:

1. 1 x PCI Express x16 slot, running at x4 (PCIEX4)
   * The PCIEX4 slot shares bandwidth with the M2P connector. The PCIEX4 slot operates at up to x2 mode when a PCIe SSD is installed in the M2P connector.

Maybe the GPU's only do 1x or 4x and skip 2x, and the boards not negotiating correctly?

 

[archvile]

Have you tried it with any different processor?

Unfortunately, no. All the CPUs I have are from previous generations which are not supported by the motherboard.

From the product page:

1. 1 x PCI Express x16 slot, running at x4 (PCIEX4)
   * The PCIEX4 slot shares bandwidth with the M2P connector. The PCIEX4 slot operates at up to x2 mode when a PCIe SSD is installed in the M2P connector.

Maybe the GPU's only do 1x or 4x and skip 2x, and the boards not negotiating correctly?

Maybe. And if that's the case, I don't think there is anything I can do other than RMAing the motherboard.

 

[londiste]

What CPU are you using?
It should not matter but just in case you have something strange

 

[archvile]

What CPU are you using?

9900K

 

[aQi]

Unfortunately, no. All the CPUs I have are from previous generations which are not supported by the motherboard.


Maybe. And if that's the case, I don't think there is anything I can do other than RMAing the motherboard.

Why not ? RMA might be possible its not an old one.
I would say if available go to gigabyte’s distributor and let them check for the concern. These lanes are not coming from the processor. These are from the chipset itself.

 

[archvile]

Why not ? RMA might be possible its not an old one.
I would say if available go to gigabyte’s distributor and let them check for the concern. These lanes are not coming from the processor. These are from the chipset itself.

This diagram is very helpful, thank you. Now I know it's definitely about the motherboard and not the CPU.

 

[aQi]

This diagram is very helpful, thank you. Now I know it's definitely about the motherboard and not the CPU.

Your welcome. But the best possible solution is to return it. There may be any electrical issue but who knows better then the vendor.