this is why I looted the 3M Riser from the Dan A4 ? ? ? and you guys with Gen4 M.2 NVME drives should also go and get a Gen4 riser
Hey I have the exact same motherboard and BIOS version and I set this option to "Gen3" in preparation for 30-series card. Your reply made me curious so I benchmarked my SSD with this option set to "Gen3" vs. "Auto".
My SSD is Corsair MP600 1TB, which is a first-gen PCI-E 4.0 SSD. From the test results it's clear that this setting affects speed of NVMe slots as well which is really unfortunate. The performance hit would be greater for those 2nd-gen NVMe SSDs that are much faster (read speed can reach 7000MB/s). Running those in 3.0 speed would be a waste of money.
Here's my benchmark results:
Hopefully there will be more gen4 compatible riser cables coming out.