New vs Used SSD Performance

We begin our look at how the overhead of managing pages impacts SSD performance with iometer. The table below shows iometer random write performance; there are two rows for each drive, one for “new” performance after a secure erase and one for “used” performance after the drive has been well used.

4KB Random Write Speed New "Used"
Intel X25-E   31.7 MB/s
Intel X25-M 39.3 MB/s 23.1 MB/s
JMicron JMF602B MLC 0.02 MB/s 0.02 MB/s
JMicron JMF602Bx2 MLC 0.03 MB/s 0.03 MB/s
OCZ Summit 12.8 MB/s 0.77 MB/s
OCZ Vertex 8.2 MB/s 2.41 MB/s
Samsung SLC 2.61 MB/s 0.53 MB/s
Seagate Momentus 5400.6 0.81 MB/s -
Western Digital Caviar SE16 1.26 MB/s -
Western Digital VelociRaptor 1.63 MB/s -

 

Note that the “used” performance should be the slowest you’ll ever see the drive get. In theory, all of the pages are filled with some sort of data at this point.

All of the drives, with the exception of the JMicron based SSDs went down in performance in the “used” state. And the only reason the JMicron drive didn’t get any slower was because it is already bottlenecked elsewhere; you can’t get much slower than 0.03MB/s in this test.

These are pretty serious performance drops; the OCZ Vertex runs at nearly 1/4 the speed after it’s been used and Intel’s X25-M can only crunch through about 60% the IOs per second that it did when brand new.

So are SSDs doomed? Is performance going to tank over time and make these things worthless?


"Used" SSD performance vs. conventional hard drives.

Pay close attention to the average write latency in the graph above. While Intel’s X25-M pulls an extremely fast sub-0.3ms write latency normally, it levels off at 0.51ms in its used mode. The OCZ Vertex manages a 1.43ms new and 4.86ms used. There’s additional overhead for every write but a well designed SSD will still manage extremely low write latencies. To put things in perspective, look at these drives at their worst compared to Western Digital’s VelociRaptor.The degraded performance X25-M still completes write requests in around 1/8 the time of the VelociRaptor. Transfer speeds are still 8x higher as well.

Note that not all SSDs see their performance drop gracefully. The two Samsung based drives perform more like hard drives here, but I'll explain that tradeoff much later in this article.

How does this all translate into real world performance? I ran PCMark Vantage on the new and used Intel drive to see how performance changed.

PCMark Overall Score New "Used" % Drop
Intel X25-M 11902 11536 3%
OCZ Summit 10972 9916 9.6%
OCZ Vertex 11253 9836 14.4%
Samsung SLC 10143 9118 10.1%
Seagate Momentus 5400.6 6817 - -
Western Digital VelociRaptor 7500 - -

 

The real world performance hit varies from 0 - 14% depending on the drive. While the drives are still faster than a regular hard drive, performance does drop in the real world by a noticeable amount. The trim command would keep the drive’s performance closer to its peak for longer, but it would not have prevented this from happening.

PCMark Vantage HDD Test New "Used" % Drop
Intel X25-M 29879 23252 22%
JMicron JMF602Bx2 MLC 11613 11283 3%
OCZ Summit 25754 16624 36%
OCZ Vertex 20753 17854 14%
Samsung SLC 17406 12392 29%
Seagate Momentus 5400.6 3525 -  
Western Digital VelociRaptor 6313 -  

 

HDD specific tests show much more severe drops, ranging from 20 - 40% depending on the drive. Despite the performance drop, these drives are still much faster than even the fastest hard drives.

Simulating a Used Drive SSD Aging: Read Speed is Largely Unaffected
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  • sawyeriii - Wednesday, March 18, 2009 - link

    Have you used a SSD? (If so which)

    I would state that it is not a luxary product, it is a premium product. The price difference you pay WILL translate to faster performance (if you choose correctly). More RAM only helps upto a point.

    Remember performance is based on a system of parts...
    CPU
    RAM
    NORTHBRIDGE
    GPU
    SOUTHBRIDGE
    I/O INTERFACE
    HDD/SDD

    Microsoft's Windows Experience Index has specific flaws, but the concept is sound... The system can only go a fast as the slowest component in the system (relative to the amount of time used by that component).
    Reply
  • Testtest - Wednesday, March 18, 2009 - link

    ... there's also Supertalent's Ultradrive ME (MLC) and LE (SLC) and Photofast's G-Monster v3

    At least the Supertalent drives are quite a bit cheaper with the same drive layout/controller than the Vertex drives and only differ in the firmware (which isn't bad either).

    It's however possible at least with the Ultradrive ME currently to provoke a kinda timeout error after they've been fully filled once and then still beeing written on. I don't own a Vertex so I can't test that there but if it was a controller issue, it should pop up there sooner or later as well (if you take a look in their suppport forum some error reports seem very similar).

    Intels have their 80% bug, Indilinx drives have their issues too it seems - let's hope that firmware can cure it!

    Great article btw!
    Reply
  • iwod - Thursday, March 19, 2009 - link

    Both SuperTalent and OCZ 30 / 32 GB drive cost exactly the same on NewEgg
    $129
    Reply
  • strikeback03 - Thursday, March 19, 2009 - link

    If you get Newegg's specials, one of the codes is for the 30GB for $103 with a $20MIR, so $83 with shipping if the rebate comes through. At the size I would want (~120) the Super Talent undercuts the OCZ slightly.

    Does anyone know if you can install the firmware of one maker to another maker's SSD? For example, assuming both the Ultradrive ME and the Vertex use the same Indilinx controller, and say Super Talent chose to release it with the firmware which optimizes for higher sequential speeds, would the user be able to choose the firmware which optimizes for less latency?
    Reply
  • Testtest - Wednesday, March 18, 2009 - link

    Ah, no editing?!

    A-Data's "300 plus" SSD also uses the Indilinx controller.
    Reply
  • vailr - Wednesday, March 18, 2009 - link

    "The Anatomy of a SSD" should instead read: "The Anatomy of an SSD" Reply
  • Flunk - Wednesday, March 18, 2009 - link

    Yes, because S is a vowel... Reply
  • abudd - Wednesday, March 18, 2009 - link

    Assuming SSD = "es-es-dee" then "an SSD" is right. If it *sounds* like a vowel, use "an". Reply
  • JarredWalton - Wednesday, March 18, 2009 - link

    Yes, *but* SSD could also be read as "Solid State Drive" instead of "ess ess dee", in which case you would say "a SSD". I tend to read it as "ess ess dee", but Anand thinks of those letters as "Solid State Drive".

    Potato, potato, tomato, tomato... let's call the whole thing off!
    Reply
  • Azsen - Thursday, March 19, 2009 - link

    When reading acronyms you're supposed to think of them as the letters, i.e. when you see RAM, you think "ram" straight off not Random Access Memory. When you see "IBM" you think "eye bee emm" not International Business Machines etc etc. It would take ages to read an article if you had to stop and think out all the full wording of acronyms as you're reading them.

    I'm going with the correction of "Anatomy of an SSD". Correct English fullstop.
    Reply

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