Samsung MZ7WD960HMHP (SV843) Read Speed Slow Down

jtr1962

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I bought three of these back in 2016. I've had no issues with them except for the fact that reads become slower in parts of the drive where data hasn't been refreshed in a while. For example:

1653086582646.png

For now my kludge for fixing this has been to defragment the drive. I use MyDefrag and the "System Disk Monthly" script which ends up refreshing virtually all the files on the disk. Of course, the only problem with this is that you end up with a few hundred GB of drive writes. And it doesn't fix the problem in areas of the disk which don't happen to be written to. However, the end result is typically much better than before:

1653086781763.png

Anyway, I recall my 500GB Samsung 840 had a similar issue until Samsung fixed the firmware. Has anyone heard of any solutions (either firmware upgrades or software similar to the Samsung Magician) which might work instead of defragging the drive? Besides the extra drive writes, the defragging routine takes something like a day and half to run. Note that Samsung Magician doesn't recognize these drives so that's out.
 

LunarMist

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I've seen that with many drives, though that is more extreme at 288GB and you are starting with slow speeds from SATA anyway. Defrag is not so good because of the write amplification, but also the block size/locations and cluster sizes are not matcthed so some NAND flash will perhaps be rewritten multiple times and some not at all. Is your system properly supporting TRIM? Have you tried formatting and rewriting the data sequentially?
 

jtr1962

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I've seen that with many drives, though that is more extreme at 288GB and you are starting with slow speeds from SATA anyway. Defrag is not so good because of the write amplification, but also the block size/locations and cluster sizes are not matcthed so some NAND flash will perhaps be rewritten multiple times and some not at all. Is your system properly supporting TRIM? Have you tried formatting and rewriting the data sequentially?
I don't think it is properly supporting trim for this particular drive. I'm still using Windows 7. I installed Smart Defrag 7.5 which has a trim and optimize option for SSDs. I ran it a few times daily. Now the HDTune results look like this:

1653779410188.png

Still the big slowdown around 288 GB but the speeds improved a little from 480 to 672 GB, and also from 0 to 288 GB. Checking a disk map from my defrag software it appears the area where the disk is still slow is where no data is currently stored.

Before I defragged the drive the speeds were horribly low on most parts of the drive where data was stored. At least the defragging got them close to 450 MB/sec. For now I'll just try using the trim feature of Smart Defrag daily and periodically check my speeds with HDTune.

I haven't done a reformat and rewrite. The drive is my boot drive, so for now I'd rather not. It appears the drive is now at least back to normal speeds on areas with data. Maybe what might work for the other areas is a program which just writes zeroes to the empty space on the drive.

BTW, I use MyDefrag 4.3.1. It lets me use scripts for complete control of the defrag process. The script I used here defrags the files and sorts them by name. That essentially rewrites the entire area of the drive which has data on it. Sometimes some of the empty spaces are used for scratchpad storage but you can't count on that. Unfortunately, MyDefrag doesn't have a script command to zero out sectors which are no longer holding data.
 

jtr1962

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I just thought of something. Earlier I mentioned my Samsung 840 did the same thing until Samsung issued a firmware fix. Since these are enterprise drives it was likely assumed new data would be written to them often enough so the stored data wouldn't degrade enough to slow down reading.(hence no need for the firmware to periodically refresh data). However, using these drives for home use that's exactly what happens because the data isn't refreshed often enough.

I'm not concerned about defragging hurting the lifespan. These are speced at 3.6 DWPD for 5 years, which is about 6300 TB. So this drive has only 16 TB of writes. A complete defrag once every few months will only add a few more TB annually.
 

LunarMist

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Just how old is it? I was running 4th gen Cores on the M.2 drives with Win 7 years ago. The earlier M.2 worked on the PICe without NVMe and then the NVMe SSDS needed a driver. More recently the Samsung NVMe SSDs don't have a driver and cannot be used.
 

jtr1962

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It's an Asus Crossblade Ranger with an AMD A10-7870K APU. Here's a claim that it can be made to boot with an M.2 drive:


Honestly I'm not about to spend the money for hardware, plus the time, just to see if it works. For now the system is plenty fast for my needs. The new Ryzen 7 5700G/GE look interesting if I was in the mood to upgrade. Any MB supporting the Ryzen 7 would obviously have NVME slots. For now though I don't really have upgrade fever.
 

jtr1962

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I might have stumbled upon a solution.

The built-in cipher command has an option to erase free space on a drive. Just use cipher /w:C It normally does three passes, writing 00, FF, and random data. I stopped it after the first pass to limit drive writes. Looks like a big improvement over the result in post #3 where I had finished defragging it:

1654240614825.png

I'll just try this every few months to keep the drive from slowing down again.
 
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