Samsung 850 PRO read speed drops on old-written files... Similar to the 840 EVO, but less critical - Overclock.net

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post #1 of 13 Old 07-29-2016, 08:58 AM - Thread Starter
 
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Hi to all,
If you remember, a couple of years ago, I started on this forum the discussion about read speed drops on the 840 EVO.

Now I own (also) a 850 PRO 1TB drive and I noticed a slow-down on old files like with the 840 EVO. The 850 PRO is installed in a PC which is 24/7 online.

Here is a scan of my actual drive:




And this is the scan after a run with Diskfresh:



"Old" files are about 2-3 months old, I didn't have the time to check that carefully.

So... Even with the 3D V-NAND we have the same problem as 840EVO but to an important less extent. Before the firmware fix, the old files in the 840 EVO dropped to 60MB/sec, in the 850 PRO they go just below 190MB/sec instead of a full speed of about 490MB/sec on my PC.

But the problem is still the same, and for a PRO drive I think it's not good at all.

What do you think? Try to scan your 850 PRO drives (with at least 1-2 months old data) and post here the results!

PS: my old 840 EVO 1TB drive with the firmware fix is running fine, no more slowdowns in the same rig... And that's better than this 850 PRO frown.gif
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post #2 of 13 Old 07-29-2016, 06:26 PM
 
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How is it possible for the 850 pro to have the same issue as the 840 evo, if the 850 pro is MLC and the 840 evo is TLC.

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post #3 of 13 Old 07-29-2016, 07:05 PM
 
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Quote:
Originally Posted by Palorim12 View Post

How is it possible for the 850 pro to have the same issue as the 840 evo, if the 850 pro is MLC and the 840 evo is TLC.

Besides MLC vs. TLC, it's also "3D-VNAND" with this drive here compared to "planar" NAND on the 840 and 840 Pro and 840 EVO drives, so overall pretty different hardware.

With the 840 EVO problem, they could fix the problem completely with a firmware update. It seems the programming of that software can have a very big influence on the performance of the whole SSD. This might be the case for any SSD, and then a mistake in the programming can make the SSD show terrible results even if the hardware should be a lot better.
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post #4 of 13 Old 07-29-2016, 08:08 PM
 
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Here's a screenshot I took from my phone that i remoted into my computer, so it might not look great. Its on 24/7 since I use it as a media server and i installed it some point in 2015.


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post #5 of 13 Old 07-30-2016, 12:34 AM
 
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Here is an result of my 850 PRO 256GB model running with the initial firmware EXM01B6Q. Also 840 EVO 1TB after EXT0DB6Q patched and 850 EVO 1TB with the initial firmware are going strongly. I haven't tested them recently because I thought the issue had gone. What happend to OP's drive?


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post #6 of 13 Old 07-30-2016, 05:13 PM - Thread Starter
 
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I was surprised, too when I did the scan & diskfresh on the 1TB 850 PRO... Looking at the scan you posted, it might be that my drive is somehow defective, even if after diskfresh now is running with the expected speed.

Maybe it's a problem related to the 1TB model... I got that one with a big discount during a "Prime day" of a famous online store smile.gif
I'm also using this drive as a data drive, the OS is on another disk.

BTW, how old is the data you have in the 256GB 850 PROs?
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post #7 of 13 Old 07-30-2016, 05:58 PM
 
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My stuff is from as far back as October, cuz thats when i went from a Z77 MB to a z170 and had to reinstall my OS onto the SSD.

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post #8 of 13 Old 07-30-2016, 08:03 PM
 
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Mine is working as an OS(Win 8.1 x64) and application drive from June last year. It's connected to Intel SATA port on Z97 chipset and Dynamic Storage Accelerator is disabled.
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post #9 of 13 Old 08-08-2016, 07:35 AM
 
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In my opinion it looks more like a false positive rather than voltage drift causing read speeds to drop.

I know that you're going to say that after running DiskFresh read speeds were restored.
But I've been in a similar situation with another drive (read speeds were also restored after using DiskFresh) which produced results that made me believe it suffered from voltage drift so bad that it was noticeable in mere days.

Said drive has now been tested for months in which it has produced pretty much nothing but steady (and somewhat boring) results with little indication of read speeds dropping.
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post #10 of 13 Old 08-08-2016, 03:48 PM - Thread Starter
 
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Yes, of course if it's only my drive and no other owners are measuring that speed drop on the 1TB model, I agree with you.
Anyway I'm sure I'll not delete at least half of the data I have on that drive in the next months. Now that the speed is restored, I'll scan the drive every month or so and I'll follow up if the speed drop returns (and maybe I'll RMA the disk if it's still on warranty).
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