Asus ROG Strix B450-F Gaming II black screen after power loss

[fanjo]

Hi guys,

I have 7 AMD gpus (mix of RX 6800 and RX 6700XT) plugged into the Asus ROG Strix B450-F Gaming II and it works very well once booted. I have 4G Decoding, Gen1/Gen 2 active etc

If I reboot my rig, there is no problem, the rig will come back up and work.

If I shutdown via HiveOS or if the power cuts, the following behavior happens:

1. I plug the power back
2. The rig powers up but never shows the bios screen, the screen stays black and never gets to HiveOS.

Solution steps:
3) Unplug all PCIe risers from the motherboard except the one plugged into the main PCIe port and power up the rig.
4) As soon as the Bios Logo shows, press DEL then go and change a setting (seems like any settings works) then save and exit. At that point, power off the rig, plug the risers back and it will boot.

Note 1: I absolutely need to modify and save the bios. If I don’t do it, with only 1 gpu, the will boot and go to HiveOS but if I shutdown and plug the gpus back, I still have the problem.

Note 2: When there is a modification of the number of GPUs plugged, I noticed that the rig will boot the first time and automatically shutdown after 1 or 2 seconds, then reboots itself.

Do you know what is going on with this motherboard? Obviously all the cards and risers are working, it’s only when I edit and save the bios that the problem is solved (until next time!)

Thanks

[sbarmen]

Hello @fanjo I have been pulling my hair out today on this same issue. Not perfectly sure what was the problem bu since I came across you post I took a picture of my BIOS settings, and now it works perfectly, even on power cut.

Hope it helps

[garciaray]

We have the same problem , when try used the pci express usb cables (SIX) , shows a failure and Ineed make a bios blash back to have a funtionality on the MB, afte this I tried use 3 GPUS directly on the Mb and the other 3 used the PCI usb xpress cables but only was detected 2 GPUS as funtionals .

[sbarmen]

Just FYI I flashed the latest BIOS update.

[garciaray]

Thanks , I use the lastest version shows on the official webpage , Wich one do you use ? …also we use a ATLHON procesador 3G AM4 RADEON VEGA , do you think that maybe this is the root cause for the issue ?

[sbarmen]

Not sure. This is my version:

Motherboard

ROG STRIX B450-F GAMING II ASUSTeK COMPUTER INC. (4502 07/13/2021)

CPU

8 × AMD Ryzen 3 PRO 4350G with Radeon Graphics

[garciaray]

We have this configuration but not works , do you have some idea that can help us ?

[sbarmen]

PCIEX16_3 set it to x1_mode.

Note, in the image above it should be set to the value LEFT of the arrow.

Check TPM specially.

[fanjo]

Hey sbarmen, this motherboard has 6 pcie plugs, how are you pluging additional 2 GPUS?
Are you using a m2 to pcie adaptors or something splitting a pcie lane?

I’m able to run 7 gpus using a m2 to pcie adaptor in M2_1 but I can’t get an 8th gpu working with an adaptor in M2_2 for some reason it’s never recognized…

[fanjo]

Guys, FYI for this specific issue, it got resolved when I purchased a very simple and cheap Power Supply Splitter from Amazon.
I’m using 2 power supplies for this rig and 1 of the power supply was always on since it was bypassed. Now that I have the splitter cable, both power supply shut down at the same time.

No more black screen since then!

[sbarmen]

I only run 5, sorry if that was unclear.

[sbarmen]

I ment 8 core AMD ryzen

[tisoloteam]

Hello,

Could you clarify please, should settings be like this ?

Selects TMP Device == Enable Firmware TPM
Onboard LED == disabled | not sure how it could affect the cards
Primary Video Device == IGFX Multi-Monitor
HD Audio Controller == disabled
PCIE16_3 Control == X1 mode
PCIE16_1 Mode == GEN2
PCIE16_2 Mode == GEN2
Wi-Fi Controller == Disabled
Bluetooth Controller == Disabled

Just on the picture it is a little confusing. It tells that settings should be on the right from “->”.

I don’t have this PCIE16_2 Mode == GEN2 for my Motherboard.
I checked all the settings.

Any ideas ?