Very slow write speed on SSD S3520

[DRobi14]

I have experienced horribly slow write performance on both my S3520 240GB drives on Windows 7, and would like some guidance.

The details:

I have 4 Intel SSDs : 2 x 530 Series (SSDSC2BW120A4 and SSDSC2BW240A4), and 2 x S3520 240GB (SSDSC2BB240G7). I have the same very disparate performance with both pairs. In addition, I have 3rd S3520 in the field with the same problem.

The pair I will highlight is as follows:

530 Series 120GB

F/W version : DC32

S/N: PHD A41 660 0Z8 120 7GN

DC S3520 240GB

F/W version : N2011021

S/N: BTD V72 750 FRY 240 AGN

The problem: I have a proprietary OS running on a Pentium server box, which has its own driver to talk to these SSDs in IDE mode. The 530 performs very well, in line with benchmark data I can find on the Web. The S3520 performs well also, except In certain cases, where its average sector write time is 26x (yes, 26) that of the 530. We have managed to produce a specific test case where we write 15,634 single sectors of a 13MB file, with specific content in each sector, and the same non-consecutive order of disk addresses being written. The average write time for sector writes to the 520 is 0.06ms, and the average write time for the S3520 is 1.56ms.

At first we thought there must be some compatibility problem between our disk driver and this specific drive.

But I have constructed a Windows program which writes these same sectors to a second pair of drives, in the same order, on Windows 7 (using FILE_FLAG_NO_BUFFERING).

The result is the same: < 1 sec to write the 15,634 sectors on the 530, and > 20 sec on the S3520.

I can only conclude that the S3520 has some severe firmware problem which makes it sensitive to the content (and/or the order) of certain data being written.

Does anyone have any experience with similar problems here?

[idata]

Hello DLRobinson,

We understand that you're experiencing slow write speed on three of your Intel® SSD DC S3520 Series.

In order to better assist you, we would like to take a better look at your system and SSDs details:

- Please download and run the https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility Intel® System Support Utility on the Windows* based system, with at least one of the Intel® SSD DC S3520 and 530 Series plugged. Select scan for "everything" then save the file to your computer.

- For specific SSD information, please download and run https://downloadcenter.intel.com/download/27130?v=t Intel® Solid State Drive Toolbox. Select the SSD and click on "Export" to get the S.M.A.R.T. details log. Do the same for both your Intel® SSD DC S3520 and 530 Series.- Additionally, run a quick https://crystalmark.info/download/index-e.html CrystalDiskMark* benchmark for both drives and take screenshots of the results.

NOTE: Links to third party sites are being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.

Please attach the resulting files to your next reply. To enable attachments, select the option to "use advanced editor" while replying.

Best regards,

Eugenio F.

[DRobi14]

Eugenio,

I have attached the info you requested. Each item is labelled by "S3520" for the 240GB S3520, or "530" for the 120GB 530 series.regardsDave Robinson

[idata]

Hello DLRobinson,

Thanks for sharing the requested logs and screenshots.Based on the system specifications, the benchmark results for your Intel® SSD DC S3520 Series are optimal. The S.M.A.R.T. logs show the drives are in perfect health as well.Regarding the firmware, there haven't been any reports on major bugs for the latest Intel® SSD DC S3520 Series release (N2010121).How exactly did you notice the slow write speed while the drives are in production?Best regards,Eugenio F.

[DRobi14]

Eugenio,

There is no question that the S3520, with the firmware version you see in my Intel Solid State Drive Toolbox report, performs very poorly with certain types of writes - either the data or the ordering or both.

We noticed the slow write speed when performing a certain type of operation in our OS. The operation is a common database maintenance task that our customers run frequently. The last phase of the operation rewrites the file of database indices - mostly binary data - the last part of this writes the file to disk one sector at a time and not in sector order. On regular non-SSD drives this operation, for average 5GB files, takes a fair while but is not unreasonable. On the 530 series SSD it takes very little time, but on the S3520 it takes literally hours - totally unacceptable.

As I explained in my original post, we have taken a small sample index file from our OS and constructed a test case that runs in Windows 7. It writes 15,000-odd sectors not in sector order and produces the same results, namely that the for the 530 disk it runs in < 1 second, but on the S3520 it takes over 20 seconds. This is reliable and repeatable EVERY time.

I have attached a copy of the test case for you to run and demonstrate the problem. Here are the details:

• FD32.EXE is the test program. Put it in a directory together with its two data files.
• You will need to turn off DATA EXECUTION PREVENTION for FD32.EXE, as it uses an old copy of the Borland runtime libraries which executes in its data.
• The two input data files are TWO20.DAT and TWO20.CSV.
• The program writes a temp file named TWO20.TMP to the location specified on the command line - see the BAT files.
• Put at least one 530 (or equivalent) and S3520 SSD on the system.
• In the BAT file TEST530.BAT, replace the 2 instances of the string "G:\" with "X:\", where X is the drive letter of the 530 SSD disk.
• In the BAT file TESTS3520.BAT, replace the 2 instances of the string "E:\" with "X:\", where X is the drive letter of the S3520 SSD disk.
• Run each BAT file and time the interval between the "Start" and "Done" messages printed by the program.
• You will find this program takes over 20 times longer to build the file on the S3520 than it does on the 530.

Please let me know if you have any questions.

regards

Dave