NVME gen4 drive almost as slow as a SATA SSD

So I just bought a batch of 7 ‘recovered’ data center NVMe drives (a complete steal for 45 USD). The model is the Micron 7450 Pro 960GB m.2 NVMe with advertised speeds of up to 5000MB/s. I already checked and tested all of them, and they are barely used, with some drives having only 4 hours of use and the highest at just 400 hours. TBW also maxes at 2TB in 2 of the drives, so suffice to say they are not really that much used. When I tested the speeds on a PCIe 4.0 x4 slot, 4 of the drives can get 5300 and even 5500MB/s reads and 1400MB/s writes (just as they should), but 2 of the drives get exactly 663MB/s reads. I have tried reformatting, reinitializing, and setting sector sizes of 512 and 4096 in Micron Storage Executive, but no luck. These 3 drives max at 663MB/s. Do you have any idea what could be causing this? Or maybe these are just damaged drives? That wouldn’t be the end of the world; I still got 4 1TB NVMe drives for 45 USD. Edit: I have tried updating the firmware via the CLI tool (MSE doesn’t let me do it) and still the same 663 speeds.

Try updating the firmware of those slow drives.

Tried it, they are on the latest firmware and the software won’t let me force the update with the same firmware.

Could there be an issue with the PCIe slot you’re using? Sometimes, slots can be faulty or not fully compatible.

I tested them in a different slot too, but got the same results. It’s really puzzling.

Have you monitored the temperatures? Overheating can throttle speeds significantly.

They’ve been running cool during tests. I don’t think that’s the issue.

Maybe the drives are locked in a low power state? Check if there are any power management settings.

I’ll look into that. Thanks for the suggestion!