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Original topic:

Samsung 980 Pro 500GB NVME M2 drive - very low write speeds

(Topic created on: 29/12/20 11:57)
First Poster
Computers & IT

Hi all,


I've noted in the last few days that my PC has felt pretty sluggish, both in starting up and also running applications. I have a Samsung 980 Pro 500GB NVME M2 drive.


Upon checking in Samsung Magician, the write speeds have nose-dived, to around 25% of what they were previously. See image attached.


I've gone through all the usual checks. Samsung Magician is updated. There's no Firmware pending. Motherboard chipset drivers are up to date. I've rebooted several times, ensuring that the PCI settings in BIOS are correct (Gen 4). Nothing makes a difference.


Notable changes to the OS in the timeframes involved would be the Cumulative Update For Windows 10 Version 20H2 which took place on the 12th of December but as you can see on the attached image, the write speed was fine on the 14th of December, so unlikely to be related. Nothing else has changed on the system.

Motherboard is MSI MEG Godlike x570 with latest BIOS and chipset drivers (via AMD directly) running a 5950x CPU. I've also attempted reinstall of the chipset drivers, which has made no difference.


I've performed a TRIM on the drive, no difference.

Can anyone help? I don't know where else to turn with this.



First Poster
Computers & IT

After having no replies here and a stock response from Samsung support directly, I did lots more digging.

Turns out, these drives suffer from cache write speed fallofs, after a period of usage. See this article..


Specifically this text..


You have to be careful when filling up the 980 Pro because it will do so quicker than you might expect. Samsung's 980 Pro sustained 100GB of writes to its TurboWrite cache at a rate of 4.5 GBps before performance degraded. Once its cache filled, write speed averaged 1 GBps until full, outwriting the competition. Cache recovery is on the slower side, however. While the static 6GB cache recovered immediately, the 'Intelligent' dynamic cache did not recover within a half-hour idle window.


What I've found, so far, is that this issue simply requires the 980 to clear its cache. I have two drives, a 500 and 1TB and both had this problem. The 1TB, after several hours of downloading games and then immediately playing a game, saw write speed drop to 1600mb from what should be about 5000mb. Leaving the PC idle for 5-10 minutes saw the write speed resume to normal.


The 500gb went through several reformat/reimage attempts, all of which failed to rectify the write problem (this was before I knew about the above issue). However, the final attempt which also included a secure erase, then saw me leave the PC idle for a couple of hours. Upon returning, the write speed was back to normal.


So if you find your 980 write speed impacted in this way and evidenced via Samsung Magician performance tests, leave your PC idle for a couple of hours and then retest. You may find the issue has been fixed, without having to waste any of your valuable time reformatting the drive or wasted with Samsung "support".