Three-Way AMD GPUs not working anymore.

[Michael Hoppins]

Updated PC's CPU from a Ryzen 5 2600 to a Ryzen 9 3900X and the three way GPU setup needed for the computer stopped working, will now only post with two cards plugged in.

Original Setup:
Ryzen 5 2600
Asus B450-F
48GB RAM
AMD RX 570s (x3)

New Setup:
Ryzen 9 3900X
Asus B450-F
48GB RAM
AMD RX 570s (x3)

The only change has been the CPU, is there any reason for this not to be working anymore?

The image attached is the latest setup. With only the middle one plugged in.

[FloRolf]

wait so it's only picking up one card now and that's the middle one oddly enough?

 

Maybe try removing all but the first one and then restock from there. Maybe the drivers are messed up or something. 

[Michael Hoppins]

3 minutes ago, FloRolf said:

wait so it's only picking up one card now and that's the middle one oddly enough?

 

Maybe try removing all but the first one and then restock from there. Maybe the drivers are messed up or something. 

This image was taken with only the middle one installed, should've make that clear.

The top one will run at 16x when plugged in (or 8x if a second is installed), then when the middle or bottom are installed on their own their will be 4x with a warning light. I've checked all the drivers, updated the bios.

[Xkillerpn]

Hello, so b boards dont run multi gpus or if they run its limited. i think you are going to need a X board. 

[Michael Hoppins]

1 minute ago, Xkillerpn said:

Hello, so b boards dont run multi gpus or if they run its limited. i think you are going to need a X board. 

The same board used to run the three GPUs perfectly until I upgraded the CPU.

[GrockleTD]

1 minute ago, Xkillerpn said:

Hello, so b boards dont run multi gpus or if they run its limited. i think you are going to need a X board. 

that doesn't make sense, as it worked before swapping the CPU

[GrockleTD]

1 minute ago, Michael Hoppins said:

The same board used to run the three GPUs perfectly until I upgraded the CPU.

on the odd chance you haven't already, clear cmos?

[Michael Hoppins]

Just now, GrockleTD said:

on the odd chance you haven't already, clear cmos?

I have cleared it yep.

[mathijs727]

Looking at the manual (page 9 / ix), I think it is expected for the second slot to run in PCIe-3 4x mode:

https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/ROG_STRIX_B450_F_GAMING/E14401_ROG_STRIX_B450-F_GAMING_UM_WEB.pdf

 

The 3rd slot is running of the motherboard chipset at PCIe-2 4x speeds.

I assume that with the 3900x (which introduced a lot of changes with respect to I/O) running a GPU over the chipset (on this motherboard?) is broken.

[Michael Hoppins]

2 minutes ago, mathijs727 said:

Looking at the manual (page 9 / ix), I think it is expected for the second slot to run in PCIe-3 4x mode:

https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/ROG_STRIX_B450_F_GAMING/E14401_ROG_STRIX_B450-F_GAMING_UM_WEB.pdf

 

The 3rd slot is running of the motherboard chipset at PCIe-2 4x speeds.

I assume that with the 3900x (which introduced a lot of changes with respect to I/O) running a GPU over the chipset (on this motherboard?) is broken.

So basically if I wanted to keep the 3900x, I've gotta switch to a more powerful board.

[mathijs727]

4 minutes ago, Michael Hoppins said:

So basically if I wanted to keep the 3900x, I've gotta switch to a more powerful board.

If I were you I would just contact Asus directly and ask what the exact problem could be and whether it can be fixed with a future bios update.

 

Also, running 3 GPUs on a low-end board is kinda weird already, especially 3 mid-range graphics cards (instead of 1 or 2 high-end ones).

[Michael Hoppins]

4 minutes ago, mathijs727 said:

If I were you I would just contact Asus directly and ask what the exact problem could be and whether it can be fixed with a future bios update.

 

Also, running 3 GPUs on a low-end board is kinda weird already, especially 3 mid-range graphics cards (instead of 1 or 2 high-end ones).

The computer was meant to be for a 9 monitor setup for a certain type of work at a news company.

[mathijs727]

10 minutes ago, Michael Hoppins said:

The computer was meant to be for a 9 monitor setup for a certain type of work at a news company.

Since this is for professional use you should look at professional hardware.

Both AMD as well as Nvidia sell hardware specifically for this use case.

Not only do those cards support way more displays per card, they also come with extra features such as unifying all displays into one virtual monitor and bezel correction:

https://www.nvidia.com/en-us/design-visualization/solutions/nvidia-mosaic-technology/

https://www.amd.com/en/technologies/eyefinity-professionals

 

With some Displayport hubs it might be possible to connect 9 displays to a single GPU (if it supports 9 displays - consumer cards are usually limited to 3 or 4):

https://www.club-3d.com/en/detail/2409/multi_stream_transport_(amst)_hub_displayportt_1.2_triple_monitor/