Basically as title says, boots to x16 gen 3 despite being set to gen 4 or Auto in BIOS (ver. 4602 agesa 1208).
The 6900 XT was running Gen 4 before on an Aorus B550i
2x gen 3 NVME SSD's
Chipset drivers are up to date
Replaced Linkup gen 4 riser cable with a new one, no difference. Testing without riser is a giant hassle due to open loop w/ hard tubes... When I've had issues with riser cables in the past it's either just refused to post until set to gen 3, or been unstable if post was successful, which aligns with other people's experiences I've seen. GPU-Z reports the bus interface as x16 gen 4, so it shouldn't be that the riser (both of them) is so broken that the motherboard doesn't even register it as gen 4, right...?
Link state power management is off in Windows.
Are there any settings in BIOS that can affect this, any PCI power saving features or whatnot that isn't mentioned anywhere on the internet?
PC runs fine otherwise, OCCT power test 1h+, tm5 absolut config no errors, no WHEA errors, no stuttering, gaming is perfect, ReBAR works. Not missing much performance but since it isn't working as intended I want to work it out so there aren't any underlying issues that may become troublesome in the future.
Happy for any feedback on things I'm hopefully overlooking
Guess I'm not alone with this problem. Still happy for feedback if anyone else has experienced it or know something else!
Vbios is stock, mobo bios is the latest, also tested with the bios it came with (3602) and 4204. Only things plugged in are GPU and nvme in front and back port. Testing without the back (chipset) nvme is unfortunately in the same category as testing without the riser. I guess I could unplug the front (cpu) nvme and boot from an usb for troubleshooting, if the shared lanes from cpu limits bandwidth for some reason.
You actually gave me a glimpse of hope there for a second. Realized the install was made on the B550i board with a 5600G which only supports gen 3 (used it to troubleshoot the 5600X I had originally as it seemed like a mobo/cpu issue initially).
Just made a fresh install along with newest gpu and chipset drivers, and same thing...