# AM4 motherboard with quad R9700's behind plx88096 ROMBAR Woes

> Source: <https://forum.level1techs.com/t/am4-motherboard-with-quad-r9700s-behind-plx88096-rombar-woes/257456#post_2>
> Published: 2026-09-30 17:37:57+00:00

So i recently got my PLX88096 chip in the mail, and have used it to install 4 R9700 AI’s onto the system, however it seems my poor prosumer grade AM4 X570-D4U-2L2T/BCM motherboard has had enough of my shenanigans and just doesnt have the BAR space to deal with it

My onboard 10Gbe also stopped working, but i suspect this is just a side effect of the lack of BAR space

I’ve added the Dmesg logs and my kernel opts

Please  obi-wan janitobi’s, you guys are my only hope:

Kernel Args:

GRUB_CMDLINE_LINUX_DEFAULT=“quiet amd_iommu=on iommu=pt pcie_aspm=off amdgpu.ras_enable=0 pci=realloc=on amdgpu.runpm=0 amdgpu.gpu_recovery=1 pcie_acs_override=downstream,multifunction, default_hugepagesz=1G hugepagesz=1G hugepages=108 transparent_hugepage=always”

DMESG: See attachment

[dmesg.txt](https://forum.level1techs.com/uploads/short-url/cuEyL12crKwewszQIO6ydsM2IAr.txt) (46.6 KB)

For your viewing pleasure(or distaste, depending on tolerance):

 

 
It WORKS!!!, it was Legacy CSM support being enabled, i have a new problem now though, even though everything is now properly showing inside the VM P2P is still disabled in AMD-SMI topology:

ACCESS TABLE:

0000:01:00.0 0000:02:00.0 0000:03:00.0 0000:04:00.0

0000:01:00.0 ENABLED      DISABLED     DISABLED     DISABLED

0000:02:00.0 DISABLED     ENABLED      DISABLED     DISABLED

0000:03:00.0 DISABLED     DISABLED     ENABLED      DISABLED

0000:04:00.0 DISABLED     DISABLED     DISABLED     ENABLED

WEIGHT TABLE:

this is inside the VM that’s being passed through all these devices