# GPU using PCIe Gen1 - why?



## hsnyder (Jan 4, 2022)

If I'm reading `pciconf -lcv` correctly, then my GPU is running at PCIe Gen 1 speed. Here's the relevant output:


```
vgapci1@pci0:67:0:0:    class=0x030000 rev=0x00 hdr=0x00 vendor=0x1002 device=0x6995 subvendor=0x1028 subdevice=0x0b0c
    vendor     = 'Advanced Micro Devices, Inc. [AMD/ATI]'
    device     = 'Lexa XT [Radeon PRO WX 2100]'
    class      = display
    subclass   = VGA
    cap 09[48] = vendor (length 8)
    cap 01[50] = powerspec 3  supports D0 D1 D2 D3  current D0
    cap 10[58] = PCI-Express 2 legacy endpoint max data 256(256) RO NS
                 max read 512
                 link x8(x8) speed 2.5(8.0) ASPM disabled(L1) ClockPM disabled
    cap 05[a0] = MSI supports 1 message, 64 bit enabled with 1 message
    ecap 000b[100] = Vendor [1] ID 0001 Rev 1 Length 16
    ecap 0001[150] = AER 2 0 fatal 0 non-fatal 1 corrected
    ecap 0015[200] = Resizable BAR 1
    ecap 0019[270] = PCIe Sec 1 lane errors 0
    ecap 000f[2b0] = ATS 1
    ecap 0013[2c0] = Page Page Request 1
    ecap 001b[2d0] = Process Address Space ID 1
    ecap 0018[320] = LTR 1
    ecap 000e[328] = ARI 1
    ecap 001e[370] = L1 PM Substates 1
```

Unless I'm mistaken, the text "speed 2.5(8.0)" means that the device is running at PCIe gen 1, when it's capable of gen 3. The only PCIe related tunable I've set to a non-default value is `hw.pci.enable_aspm="0"` in /boot/loader.conf. 

The motherboard is a supermicro H11DSi, equipped with 2x Epyc 7302 CPUs. I don't see anything in the BIOS that would allow me to control the link speed. Where might I start debugging this?


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## richardtoohey2 (Jan 5, 2022)

If you booted from a Linux live CD, what does Linux say about it - if that shows what you'd expect, then would point to something in FreeBSD.

But if the same/similar output in Linux, then maybe a hardware/BIOS setting/issue?

But trying a different OS might give a helpful clue.


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