Folks, I got serious problems with a PC I just built with a Gigabyte B550 Vision D and r5900X. Look at the figures below.
I installed all drivers for the chipset (tried both those from Gigabyte and from AMD itself..).
I even tried the pm9a1 (oem version of the 980 pro) on the Z690, it does over 90 MB/s read, ~360 write...
Are you using the top m.2 slot on your B550 board?
The top slot supports PCIe 4.0 x4 through the CPU, while the bottom m.2 slot only supports PCIe 3.0 x4 through the chipset.
The Z690 has the advantage of having more next gen PCIe lanes over the B550.
On my X570 board with 2 PCIe 4.0 m.2 slots, I still found the top slot to be faster.
Fact check this before trying as I haven't used NVME SSD's yet and have no experience with them.
I think it was in my MSI MOBO Product Manual (X370 M7 ACK). It has 2 M2 interface ports between the primary and secondary PCIE ports.
I can't locate my manual at the moment but I vaguely recall something about if using a GPU whose dimensions would cover 2 PCIE x 16 slots that it is best to use the lower slot.
Came across some videos on YouTube were claiming that large triple fan GPU's were creating EMI interference for their NVME cards. That was back when NVME was fairly new and haven't seen such videos or claims like that in a while.
Stands to reason if those M2 housing points aren't properly shielded for EMI being that close to GPU's that can produce a lot of that in a small area could cause some issues.
Once again no experience with NVME cards but EMI I have dealt with in various electronic systems for 36 years and I know it can cause a lot of annoying issues in audio/video systems.
Thanks for your reply.
Consider that I occupied BOTH the NVMe slots, and I have very bad performance with both of them.. OTOH I have a gpu installed just over one of my ssds in my Intel system, and yet it works as expected...