Shockingly slow SSD performance

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Llathos

Limp Gawd
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Mar 16, 2005
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I'm running on an ultrabook: the Asus UX31. The drive in question is the SanDisk SSD U100 256GB.

I've heard some reports of sluggish performance in cases, but after running CrystalDiskMark on it, I'm concerned it actually might be failing. I have the drive partitioned into a C and D partition of 95GB and 135GB respectively.Here are my performance numbers from that run:

Code: 
-----------------------------------------------------------------------
CrystalDiskMark 3.0.2 Shizuku Edition x64 (C) 2007-2012 hiyohiyo
                           Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

           Sequential Read :   441.011 MB/s
          Sequential Write :   183.141 MB/s
         Random Read 512KB :   225.911 MB/s
        Random Write 512KB :    18.335 MB/s
    Random Read 4KB (QD=1) :    10.767 MB/s [  2628.6 IOPS]
   Random Write 4KB (QD=1) :     8.521 MB/s [  2080.3 IOPS]
   Random Read 4KB (QD=32) :    28.358 MB/s [  6923.4 IOPS]
  Random Write 4KB (QD=32) :     7.123 MB/s [  1739.0 IOPS]

  Test : 1000 MB [C: 76.1% (72.6/95.4 GB)] (x5)
  Date : 2012/12/20 13:20:18
    OS : Windows 7 Home Premium Edition SP1 [6.1 Build 7601] (x64)

Code: 
-----------------------------------------------------------------------
CrystalDiskMark 3.0.2 Shizuku Edition x64 (C) 2007-2012 hiyohiyo
                           Crystal Dew World : http://crystalmark.info/
-----------------------------------------------------------------------
* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

           Sequential Read :   466.864 MB/s
          Sequential Write :   306.601 MB/s
         Random Read 512KB :   249.495 MB/s
        Random Write 512KB :    10.329 MB/s
    Random Read 4KB (QD=1) :    15.150 MB/s [  3698.7 IOPS]
   Random Write 4KB (QD=1) :     9.593 MB/s [  2342.0 IOPS]
   Random Read 4KB (QD=32) :    29.326 MB/s [  7159.6 IOPS]
  Random Write 4KB (QD=32) :     6.560 MB/s [  1601.7 IOPS]

  Test : 1000 MB [D: 48.8% (66.0/135.1 GB)] (x5)
  Date : 2012/12/20 13:11:53
    OS : Windows 7 Home Premium Edition SP1 [6.1 Build 7601] (x64)


I've watched transfers of data between partitions drop to under 10 MBps. What the hell?

Is it the partitioning causing the issue? Does the drive really suck THAT bad? This is sub-USB 2.0 performance...

Any suggestions would be helpful and appreciated...
 
What are you worried about, exactly? The 4KB QD1 and QD32 numbers?

What driver are you using?

You should run AS-SSD and/or ASU (Anvil storage utilities) and post a screenshot.
 
I'm worried about the fact that these numbers are slower than anything I've seen shy of a USB 1.1 device from 10+ years ago and wondering if this is a symptom of an impending drive failure. It's not just synthetic. As I said...copying a block of data files from one partition to the other transfers at 5-10MBps.

It's horrendous.
 
Really.....really bad.

AS-SSD Results


In IOPS


The access times are shockingly bad too. .475 and .940 ms are good compared to mechanical, but modern SSDs are producing times like .03 to .1 ms access times. This is 400-900% slower.
 
Last edited:
This is SanDisk SSD U100, what do you expect?
Some lucky ones got ADATA with it.
 
The U100 is known to be fairly slow. Your AS-SSD looks similar to what others have measured:

zE2QO.png


Your sequential write is lower, but otherwise looks similar to what someone else measured for a U100 with AS-SSD.
 
Yeah I'm realizing now this is a problem with the particular flavor of poo that Asus packaged in this ultrabook.

Still, I have a hard time understanding the real-life speeds. In what world does transferring between two partitions on the SAME DEVICE result in <10MBps speeds? No modern mechanical drive in existence would go that slow.
 
MissJ84 said:
Try running Prime95 on a single thread and run AS SSD again.
Click to expand...

That is worth a try, but I guess the U100 is just slow.

Another hail mary you could try is to put a check-mark in the box in the Device Manager / Policies tab for the U100 to "Turn off Windows write-cache buffer flushing on the device".

5HG5R.png


But I wouldn't expect much improvement with either method.
 
Llathos said:
In what world does transferring between two partitions on the SAME DEVICE result in <10MBps speeds? No modern mechanical drive in existence would go that slow.
Click to expand...

That is not necessarily true. The random 4K speeds on HDDs are around 1MB/s or less. If you are copying a lot of small files from one spot on the drive to another, it can be quite slow.

By the way, you can try the AS-SSD Copy-Benchmark as well. It is under the Tools menu.

Most 2.5" SSDs have 8 parallel channels between the flash and the controller. I don't know how many the U100 has, but I guess it is less. Which hurts even more when you are both reading and writing to the same drive.
 
Last edited:
Aesma said:
466MB/s is certainly not USB2 or USB1 territory...
Click to expand...

I was clearly not talking about the sequential read speeds :)

It was the 5-7 MBps transfer rates between partitions that got my attention...and yes that's between USB 1.1 (1.5MBps) and USB 2.0 (~20MBps) speeds.
 
Well whats the size of the files you're transferring? If they are small then it will be slower, if they are hundreds of megs or gigs they should reach close to the max speed of the drive.
 
Llathos said:
I was clearly not talking about the sequential read speeds :)
Click to expand...

No, it was not clear at all what you were talking about. Which is why my first question asked you to clarify. Which you never really did.
 
JoeComp said:
No, it was not clear at all what you were talking about. Which is why my first question asked you to clarify. Which you never really did.
Click to expand...

Strange. You seem to have understood my question and replied to it just fine with the information I provided.

Here's a comparison with a Corsair M4 in a different machine:

jSjvj.png



Amazing the difference. In my ignorance, I presumed to think that an SSD would be significantly faster than a mechanical drive in all respects. This particularly shitty SSD has made it clear that's not always true. I can't recall the last time I did a copy between partitions on a mechanical drive and got down into the single digits of MBps copy speed. Even with many smaller files...
 
Llathos said:
Strange. You seem to have understood my question and replied to it just fine with the information I provided.
Click to expand...

And you still have not provided the information requested, and you still make the incorrect claim that it is slower than an HDD.
 
I thought he was talking about random access time of the USB 1.1 drive compared to this SSD 'right off the bat'..
 
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