M.2 4TB NVMe SSD copy and write speeds are vastly different

[NeghVar]

I am upgrading my NAS. I am using the USB 3.0 port on the front of the NAS. I copied all the data off onto some spare HDDs and a 4TB SSD. Copying speeds off the NAS to the HDD and SSD were good. Copying speed of the data back onto the NAS was good for the HDD. However, copying back onto the NAS from the SSD is going about 2-3 MB/s. Same enclosure, same cable, same port. Any explanations?

 

[mwroobel]

With the generic info you provided we can do barely more than guess. What NAS, What OS, Whose USB adapter and version, Specifics on the drives, have you tried any other cables etc? What is running ON the NAS, Docker, containers, VM, Plex, etc? What was the Memory and CPU utilization of the NAS when you were copying over?

 

[NeghVar]

Enclosure: SABRENT USB 3.1 Aluminum Enclosure for M.2 NVMe SSD in Silver (EC-NVME)
SSD: SAMSUNG 980 PRO SSD 2TB PCIe NVMe Gen 4 Gaming M.2 Internal Solid State Drive Memory Card
NAS: DS415+ (CPU: INTEL Atom C2538, Speed: 2.4GHz, Cores: 4, Memory: 2GB)
OS: OS included with NAS
HDD on NAS: 4x WD60PURX in RAID 5
Yes I tried 2 other cables
What is installed on NAS:

Utilization of NAS during copying

 

[mwroobel]

Well, it doesn't look like a contention issue with the NAS at time of copy. What it sounds like is that either the Synology downshifted your USB connection to 1.1 because it didn't like the time you plugged in the SSD, or the port is starting to fail. If you plug it into one of the rear USB3 ports, does the problem resolve? If you unplug and replug the SSD, does it resolve? Unfortunately, you have an ATOM C2xxx processor in that box, which is known to die an early death due to a processor design issue (You can fix it before it happens, or stop it from happening with a single resister fix, google it for more info.)

 

[NeghVar]

More odd behavior. I started a copy of a folder. It was a few MB/s. I did it again, same results. Tried again about 30 min. later, 74.1MB/s. Never unplugged it or restarted the NAS. Spontaneous result?
This is a NAS from work 5 years ago. They upgraded to a QNAP with 8 bays. And as for me getting a new one, they cost money.