x570 Taichi Bios PCI-E Gen for BOTTOM SLOT (PCIE5)

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I have an x570 Taichi and am attempting to use some external risers to power some extra GPUs. The PCI-E GEN 4.0 speeds are not supported by the risers, so I need to lower all of the PCI-E socket speeds to 3.0.

I have tested on BIOS 3.8 and 4.0, and am UNABLE to change the speed of the BOTTOM PCI-E slot (PCIE5) which I know is controlled by the x570 Chipset.

The BIOS has several options under the ADVANCED -> AMD PBS Menu related to this:

PCIe x16 Bus Interface
PCIe x8 Bus Interface
Chipset Bus Interface

I tested by plugging an NVIDIA 3060 into ALL of the slots simultaneously. 

The TOP GPU slot was changed by the BIOS option x16 bus interface. Makes sense,  (GEN1-4) all reported correctly in GPU-Z after the change.

The MIDDLE GPU slot was changed by the BIOS option 'x8 bus interface'. Also makes sense. Worked as expected.

The BOTTOM GPU slow (PCIE5 on the mobo) NEVER CHANGED despite every setting attempt I made. I assumed the "Chipset Bus Interface" would control this slot, but switching it between GEN1-GEN4 had no affect. The slot always reported as PCI-E GEN 4.0 in GPU-Z after testing. The other settings mentioned above also had NO AFFECT on the BOTTOM GPU slot.

At the moment this is limiting my ability to connect additional GPU's to my x570 board as the remaining x1 slots AND the bottom GPU SLOT seem STUCK on GEN 4.0 PCIE.

Is the BIOS broken? I assumed "Chipset Bus Interface" would be the right setting I needed to change, but it did not work.

Did this ever work in older versions? I've only tried BIOS 3.8 and 4.0.

Can anyone from ASRock please help here?

Thanks very much for your time.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
apocalypseCow Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Feb 2021 Status: Offline Points: 13	Post Options Post Reply Quote apocalypseCow Report Post Thanks(0) Quote Reply Topic: x570 Taichi Bios PCI-E Gen for BOTTOM SLOT (PCIE5) Posted: 18 Feb 2021 at 6:10am
	I have an x570 Taichi and am attempting to use some external risers to power some extra GPUs. The PCI-E GEN 4.0 speeds are not supported by the risers, so I need to lower all of the PCI-E socket speeds to 3.0. I have tested on BIOS 3.8 and 4.0, and am UNABLE to change the speed of the BOTTOM PCI-E slot (PCIE5) which I know is controlled by the x570 Chipset. The BIOS has several options under the ADVANCED -> AMD PBS Menu related to this: PCIe x16 Bus Interface PCIe x8 Bus Interface Chipset Bus Interface I tested by plugging an NVIDIA 3060 into ALL of the slots simultaneously. The TOP GPU slot was changed by the BIOS option x16 bus interface. Makes sense, (GEN1-4) all reported correctly in GPU-Z after the change. The MIDDLE GPU slot was changed by the BIOS option 'x8 bus interface'. Also makes sense. Worked as expected. The BOTTOM GPU slow (PCIE5 on the mobo) NEVER CHANGED despite every setting attempt I made. I assumed the "Chipset Bus Interface" would control this slot, but switching it between GEN1-GEN4 had no affect. The slot always reported as PCI-E GEN 4.0 in GPU-Z after testing. The other settings mentioned above also had NO AFFECT on the BOTTOM GPU slot. At the moment this is limiting my ability to connect additional GPU's to my x570 board as the remaining x1 slots AND the bottom GPU SLOT seem STUCK on GEN 4.0 PCIE. Is the BIOS broken? I assumed "Chipset Bus Interface" would be the right setting I needed to change, but it did not work. Did this ever work in older versions? I've only tried BIOS 3.8 and 4.0. Can anyone from ASRock please help here? Thanks very much for your time.

apocalypseCow Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Feb 2021 Status: Offline Points: 13	Post Options Post Reply Quote apocalypseCow Report Post Thanks(0) Quote Reply Posted: 18 Feb 2021 at 11:02am
	BIOS Settings Page when selection a Bus Interface: Setting them all to GEN1 shows the problem clearly: WHILE running a program on all cards to ensure full load, checking PCIE gen speeds via GPU-Z shows that the 3080 (in BOTTOM GPU SLOT, PCIE5) is locked at PCIE gen 4.0. No combination of settings could change this, I tried them all.

RXXP Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 14 Mar 2021 Status: Offline Points: 30	Post Options Post Reply Quote RXXP Report Post Thanks(0) Quote Reply Posted: 14 Mar 2021 at 11:01am
	I'm having the exact same issue. On bios 4.0 as well. This is really annoying.