When I install a Mellanox Connectix-5 Ex (PCIe 4.0 x16) in my ASUS Pro WS WRX90E-SAGE SE it fails to boot.
First it takes extremely long to post on the first post and fails to boot windows, then it fails to get out of post completely.
Mellanox Connectix-5 (PCIe 3.0 x16) work fine, also the Connectix-5 Ex seams to works in other systems although these are older systems with PCIe 3.0 only.
Downgrading the port link speed in UEFI before installing the card to 3.0 on the WRX90E Board did not change anything.
Really no one?!
So after the attempts to get the card running my PC started has 1 BSOD and faild to resume from hibernation 2 times.
After I reset the CMOS lickely its reliabel again, so whatever is the issue it messed up the NVRAM.
By now I also teste dthe card with an other pcie 4.0 system and in it it als works fine.
Not sure what I should do now?
Try a Connectix-6?
do a firmware upgrade, my CX-5 works with PCIe4.
I have one in AM5 and another in an Epyc system.
I also had a problem in the AM5 system, which was gone after the firmware update version 16.35.2000.