insufficient Capture Peformance Decklink Quad2 on AMD EPYC

Dear Support,

We see insufficient Capture Peformance Decklink Quad2 on AMD EPYC.

Hardware:
Hewlett Packard HP DL385Gen10 Plus with 2 x AMD EPYC 7F2.
Reported ChipSet: Advanced Micro Devices, Inc. [AMD] Starship/Matisse

Software:
Issues on either Ubuntu 20.04 LTS or CentOS 7.6
Decklink SDI 11.6 /and SDK.

Setup:
Decklink Quad2 with 8x 3G SDI Input 1080P59.94

Capture ONE 3G SDI shows expected Framerate 59.94 afps

Capture EIGHT 3G SDI shows Framerate < 50 fps, though CPU-Performance is <10% (only Capture to /dev/zero)

Also tried newest Version 11.7

also tried different PCIe-Slots on different Risers

also tried different BIOS-Settings, limiting to PCIe 3/2 (as AMD supports 4)

but no luck

That's a pity - such a powerful Server, incapable using with Blackmagic Video-Capture ...

I don't know about EPYC but Blackmagic is aware of issues with the Decklink Quad and 1'st gen Threadripper. They were able to confirm it on their end.

That support ticket is still open, six months later.