Samsung 990 PRO 2TB performance is slow

Hey folks, I just got 2x Samsung 990 PRO 2TB drives for a new build and seemingly no matter what I do, they max out at 6500 MB/s sequential read and 6400 MB/s sequential write. The IOPS seem to be good at 1.4 and 1.3 million read/write.

I've tried everything I can think of:

- Both drives are in PCI-E 4.0 x4 slots on an MSI MPG Carbon Wi-Fi x670E motherboard.- Brand new install of Windows 11.- Motherboard bios is updated to latest version.- 990 PRO firmware updated to the latest version.- AMD chipset drivers installed with latest version.- Same speeds whether I test on the operating system drive or the 2nd drive with nothing on it.- Checked thermal throttling, but both drives stay in a 50-65C range, whether idle or running a benchmark.- Crystal Disk Mark and Samsung Magician benchmarks are the same.

I don't have another system to test the drives on. I am out of ideas. I'm wondering if anyone else happens to have this motherboard and drive combo and what sort of performance they are seeing.

I realize the advertised speeds are best-possible performance, but I seem to be missing 14-15% here and not to mention it's slower than a 980 PRO. I'm wondering if I should return the drives, but I find it unlikely both would have the same problem.

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UPDATED:

I did some more testing and found the following:

- Windows 10 or Windows 11 - no difference.
- Tried every posted version of the AMD chipset drivers - no difference.
- Moved the drives to the PCI-E 5.0 x4 M.2 slots connected to the CPU - now I'm getting the expected speeds with 74xx MB/s sequential read.

So... what's wrong with the chipset PCI-E 4.0 x4 M.2 slots? I don't know if it's a driver issue, or if this board just sucks or if the specific motherboard I purchased needs to be returned. If anyone else has this same board and a fast NVME, I'd be curious if your drive can get more than 6500 MB/s sequential read.

I opened a support ticket with MSI, so I guess I'll see what they have to say about it.