Preliminary results for Crucial BX200 concerning degraded read speeds

Glaring_Mistake

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Mar 2, 2015
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Some of you might remember the thread I created earlier about the ADATA SP550 suffering from read speed degradation.
In which I said I would test several SSDs to find out if they suffered from this issue as well and let you know if that was the case.

I'm still running my tests, but for one of these SSDs it's read speeds dropped so quickly I thought I should let you know.
As you may have already guessed considering the title of this thread that SSD is a Crucial BX200.


At first I thought that the results were due to HD Tune Pro sometimes needing some time to get warmed up.
However after three weeks of testing I analyzed the results a bit more closely and noticed that it read speeds went back to normal about the same time as it reached the unused areas of the SSD.

And as I got more results it became more and more clear that it's read speeds were dropping and dropping faster than those of any SSD I'm currently testing.


Here you can see the results of the tests I've performed every week to measure read speeds.

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This is after one week and 20GB.
You can see that read speeds are back to normal around 20GB.


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This is after two weeks and 40GB.
Read speeds recover at about 40GB.


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This is after three weeks and 60GB.
Like with the others read speeds are fine after it reaches the unused portion of the SSD.
Here it is starting to become clear that read speeds are dropping thanks to that curve becoming a bit more uneven making it less likely that the earlier results were solely due to HD Tune Pro.


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This is after four weeks and 80GB.
You can see that where there was a drop in read speeds earlier it has recovered quite a bit but at the same time read speeds for the more newly written sections are dropping.


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This is after five weeks and 100GB.
Here you can see the biggest drop in read speeds so far which suggests that LDPC can raise read speeds but that the effect is temporary.


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This is after six weeks and 120GB.
Don't know I have to add anything else other than that the read speeds keep dropping.


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This is after seven weeks and 140GB.
Like before you can see that where before there was a particularly large drop in read speed it has recovered quite a bit at the same time read speeds for the more newly written sections are dropping.




I believe that the results from the first four weeks may be affected by HD Tune Pro right at the start of the read but even if I feel a bit skeptical of the really low read speeds right at the beginning you can still see that the read speeds have started to drop.
The results also show that they are dropping fast, with several examples of it dropping 50-100MB/s from one week to the next.

And even if LDPC ECC is better at adjusting for things like age and temperature than the more common BCH ECC and BX200 can use it to increase read speeds after I have read the entire SSD it doesn't prevent read speeds from dropping.


Perhaps you would like to know how I have tested the BX200 so far?
2016-01-29 I added one folder at 20GB filled with files at 20MB and after having left it unpowered for a week I tested its read speeds with HD Tune Pro 5.60 and added another folder at 20GB filled with files at 20MB.
Which has been repeated every week.


Other SSDs besides the BX200 may use the same NAND.
The Patriot Blast SSD does.
I suspect that for example the Corsair Force LE does.
And I have heard that ADATA intends to replace the SK Hynix NAND in the SP550 with the 16nm TLC NAND found in the BX200 if they haven't already.

While the ADATA SP550 is not particularly fast with the original SK Hynix NAND and can suffer from degraded read speeds in certain situations the NAND found in the BX200 is even slower and (according to these tests) significantly more prone to read speed degradation.
Let's put it this way: The BX200 has been the SSD for which read speeds have dropped the fastest of the SSDs I'm currently testing with the ADATA SP550 taking second place.
Read speeds for the ADATA SP550 have dropped by about 50MB/s over eight weeks of testing, while the BX200 has seen drops in read speeds over 100MB/s from one week to another.
And that's excluding the really low results because of the difficulty in determining if HD Tune Pro affected them.
Also note that both SSDs were tested in the same way and in the same conditions.


As I said earlier in the thread about the ADATA SP550 these results do not neccesarily mean that the BX200 has issues with low read speeds regardless of situation, most of which these tests do not cover.
That it is left without power for a week hardly affects its read speeds positively.
But the fact that I scan the entire SSD every week gives it the opportunity to identify and correct those areas with low read speeds which does affect read speeds positively.
Maybe it is just very sensitive to being left unpowered or that it needs time to go through the SSD when it is idling to fix this issue before it has gone as far as it already has.
But that hasn't been part of the tests I have performed (so far at least).
 
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Glaring_Mistake

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Mar 2, 2015
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ATTO disk benchmark would have been better to track this.
Why?

As far as I know ATTO writes files before reading them meaning that unless read speeds were dropping in a matter of minutes or probably more accurately in a matter of seconds ATTO would report perfectly fine read speeds.

HD Tune was also often used to benchmark 840 EVOs to highlight read speed issues back in the day and well, still is.
I also think that the results you get from HD Tune are easier to read than those you get with for example SSDReadSpeedTester.
 

Hellhammer

AnandTech Emeritus
Apr 25, 2011
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I also think that the results you get from HD Tune are easier to read than those you get with for example SSDReadSpeedTester.

Have you run SSDReadSpeedTester to confirm your findings (simply post here if you have trouble interpreting the results)? The issue with HD Tune is that it hasn't really been designed to benchmark a drive with data on it where readable IO sizes can vary greatly, so I would run SSDReadSpeedTester before making any further conclusions.
 

Glaring_Mistake

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Mar 2, 2015
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Have you run SSDReadSpeedTester to confirm your findings (simply post here if you have trouble interpreting the results)? The issue with HD Tune is that it hasn't really been designed to benchmark a drive with data on it where readable IO sizes can vary greatly, so I would run SSDReadSpeedTester before making any further conclusions.

There are mainly two portions of the tests I'm conducting for the BX200.

This is part one where I fill it up with folders at 20GB, test read speeds with HD Tune Pro and then leave it unpowered for a week.

While in part two I then leave it unpowered for a month before testing it with SSDReadSpeedTester.

I always intended to include SSDReadSpeedTester in my testing of my SSDs, it is why the date when the files were written is included in the name of every folder.
To make it easier to see just how old the files were.
Also decided to make the files 20MB to reduce the risk of size having an effect on read speeds.
 

BSim500

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Jun 5, 2013
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I'm not surprised. After the Samsung 840 it amazes me how any SSD manufacturer still thinks small process + TLC is a good idea. The only "solution" to this stuff is firmware that's set to constantly rewrite all data every few weeks. And still no tech site is doing any serious in-depth data retention studies, both powered stale data and unpowered. Instead we've got useful idiots declaring all we need to do is skimp even more on quality to get the price down and these things will be "replacing" HDD's as backup drives for critical data... D:

I did a read speed test of my own a while back on a Crucial MX100 (16nm MLC). 13-14 month old stale data was still being read at over 520-550MB/s. Zero errors / RAIN recovery count. From now on, I'm not even going to look at any TLC based SSD's (even Samsung' 40nm EVO's). It's MLC or nothing for me. In any case, good job with the testing. :thumbsup: It's nice to see someone having a go at this stuff.
 

Glaring_Mistake

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Mar 2, 2015
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Happy to hear that you appreciate my testing read speeds of SSDs.

And for BSim500: The 850 EVO is one of the SSDs I'm testing so if read speeds drop for that one too, I will report it as well.
Well, actually I'm testing several SSDs covering almost all NAND which is used for (consumer) SSDs today ranging from 15nm TLC to 40+nm 3D MLC.
 

Glaring_Mistake

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I guess samsung isn't the only one with sub 20nm TLC issues.

I think my earlier thread on read speeds dropping for the ADATA SP550 kind of proved that already.

They both use the SM2256 as their controller and they behave pretty similar except that read speeds seem to drop much faster for the BX200.
 

Glaring_Mistake

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Mar 2, 2015
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Have you run SSDReadSpeedTester to confirm your findings (simply post here if you have trouble interpreting the results)? The issue with HD Tune is that it hasn't really been designed to benchmark a drive with data on it where readable IO sizes can vary greatly, so I would run SSDReadSpeedTester before making any further conclusions.

Here is a picture of the result with SSDReadSpeedTester:
PNt7vk.png


Let me know if you want to see read speeds for all files.
 

Hellhammer

AnandTech Emeritus
Apr 25, 2011
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Thanks. This is proof that read speed for old files is slower, meaning that the BX200 (and other SM2256 based drives) seems to have the same issue as Samsung 840 EVO did.
 

PliotronX

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Thanks. This is proof that read speed for old files is slower, meaning that the BX200 (and other SM2256 based drives) seems to have the same issue as Samsung 840 EVO did.
And the 840 non-EVO which never received a firmware update to refresh cells on a regular basis as was done for the EVO. Last week I dealt with two different machines with such drives that were transferring older files at less than 1MB/sec. The non-EVO users only course of action as recommended by Samsung support is to run a utility called disk fresh but it never really returned the drives to full speed for us. Sad to see Crucial fall into the same rut.
 

VirtualLarry

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And the 840 non-EVO which never received a firmware update to refresh cells on a regular basis as was done for the EVO. Last week I dealt with two different machines with such drives that were transferring older files at less than 1MB/sec. The non-EVO users only course of action as recommended by Samsung support is to run a utility called disk fresh but it never really returned the drives to full speed for us. Sad to see Crucial fall into the same rut.

TLC man... "to be avoided". Yeah, the price is tempting. I bought a BX200. Haven't installed it yet. Don't want TLC in my personal rigs.

A little scared about the controller / NAND "switcher" companies. (Silicon Power, Kingston, PNY, thus far.) Wondering if they would go so far as to swap a drive that used to be MLC with a TLC controller and TLC NAND, without informing anyone. That's a really scary thought. (Could even undermine consumer confidence in the entire SSD market. Or maybe everyone just switches to Samsung "Pro" and Intel SSDs.)
 

Coup27

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Jul 17, 2010
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Nice little program. I know a few people have been wondering if the 850 EVO suffers from the same issue so I just tested it and the results are below. Average read was actually 527MB/s not what's displayed below. This is because I wasn't able to reboot my machine before running the test and looking at the TSV full results some files got RAM cached so I manually deleted those from the TSV results. The only issue I have is with the program itself as I bought this SSD in December 2015 and installed Windows 10 the same month yet on some of the files it's reporting an age much beyond that.

SSD.png


Full Results
 
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Hellhammer

AnandTech Emeritus
Apr 25, 2011
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Sometimes installed programs simply come with files that were created a long time ago. The good news is that the 850 EVO doesn't have this issue as read performance is not dictated by the age of the file (but still varies depending on the file size, but that's nothing new).
 

Glaring_Mistake

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Mar 2, 2015
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Update may be a bit late this time but here you can see the results from the the latest test.

20160422173417Result.png



I’ll have to say that it is an impressive result seeing as the average read speeds are higher than last time despite it being unpowered for four times as long as usual.
It is also made clear that BX200 can adjust for voltage drift and that it may be triggered when reading files with lower read speeds even if it doesn’t have as much of an impact every time.
 

BSim500

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Jun 5, 2013
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Update may be a bit late this time but here you can see the results from the the latest test.

I’ll have to say that it is an impressive result seeing as the average read speeds are higher than last time despite it being unpowered for four times as long as usual.
It is also made clear that BX200 can adjust for voltage drift and that it may be triggered when reading files with lower read speeds even if it doesn’t have as much of an impact every time.
Thanks for the update. Again, it's nice to see someone testing this stuff.:thumbsup: Biggest question is - if a drive slows down over 8 weeks then suddenly read speeds jump up again, is it because the drives firmware has been set to transparently rewrite the data in the background every few weeks? I'm not sure if SSDReadSpeedtester can check for this as it goes by file-name (which the low level SSD wear-levelling algorithms presumably retain).

I guess the obvious question there is how fast does "Background Program Page Count" rise relative to actual written data and does the Write Amplification Factor keep rising relative to normal use. Eg, if you 75% filled an SSD with data, recorded Host & Background blocks written, unplugged it for 8-12 weeks then plugged it back in again just idling, and tens of Gigabytes of started getting written in the background, then it would become obvious what was happening.

In any case, keep up the good work! It's stunning that in 2016, we still have a load of junk SSD benchmarks like 45mins of constant Q32 4K writes (which absolutely nothing does), yet nothing on whether the flash can actually hold a charge for very long without resorting to tricks to hide that...
 
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Glaring_Mistake

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Thanks for the update. Again, it's nice to see someone testing this stuff.:thumbsup: Biggest question is - if a drive slows down over 8 weeks then suddenly read speeds jump up again, is it because the drives firmware has been set to transparently rewrite the data in the background every few weeks? I'm not sure if SSDReadSpeedtester can check for this as it goes by file-name (which the low level SSD wear-levelling algorithms presumably retain).

Even if I have not seen as big an improvement as this with BX200 before or with ADATA SP550 (they use the same controller) previous tests have shown that they are able to improve read speeds after the files/drive have been read.
Likely without rewriting files since neither of them have ever managed to restore read speeds entirely.
My guess would be that it is the LDPC adjusting for conditions that happens to be behind the improvements in read speeds from one test to the next.

Don't think SSDRST would be able to determine that files were rewritten, at least that is not my experience.


I guess the obvious question there is how fast does "Background Program Page Count" rise relative to actual written data and does the Write Amplification Factor keep rising relative to normal use. Eg, if you 75% filled an SSD with data, recorded Host & Background blocks written, unplugged it for 8-12 weeks then plugged it back in again just idling, and tens of Gigabytes of started getting written in the background, then it would become obvious what was happening.

Since I'm not writing anything to that BX200 anymore and it is it unpowered for four weeks at a time I could note what the current amount of data written to it is and if it increases with time.
It may not be left idle very long but then it wasn't when this big improvement happened either.
Just have to remember to check that the next time I'm running tests.
 

Glaring_Mistake

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Posting a bit late once again but here you can see the results from the latest test.
20160520173026Result.png


So, read speeds are once again decreasing.
 

BlueWeasel

Lifer
Jun 2, 2000
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So, what can be done if your boot drive is suffering from degredation?
Is the only option to secure erase and reinstall?
 

Elixer

Lifer
May 7, 2002
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So, what can be done if your boot drive is suffering from degredation?
Is the only option to secure erase and reinstall?

Yeah, that is the only "fix" that will work, but, as you can see, it isn't a permanent fix.
 

BlueWeasel

Lifer
Jun 2, 2000
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Secure erase sanitizes the SSD and is supposed to restore the cells to "factory fresh" performance.

I've always used SE (usually via Parted Magic) whenever I have to reinstall Windows. Not sure if it's really necessary, but it makes me feel good.

As far as I know, it can be used on all SSD's. I've had no problem using SE on OCZ, Kingston, and now Samsung drives.