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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  • BLHealthy4life - Sunday, April 12, 2009 - link

    found it....

    Intel obviously keeps the X58 chipset drivers current for their own boards, just not other mfgs boards....

    They installed fine on my R2E..

    BL
    Reply
  • irondukes - Friday, April 03, 2009 - link

    Hi-- Do SLCs suffer from performance degradation, or are the controllers pretty agressive at erasing the data since they have far longer read-write cycles? Please help! Deciding between an X25E and X25M Reply
  • mdavies - Friday, April 03, 2009 - link

    I'm reading this about a day late - got my Patriot PE256GS25SSDR 2.5" 256GB yesterday since I'm bad about destroying hard drives. this drive, in a word, was excruciating. I'll be replacing it with one of your recommended drives today.

    Thanks
    Reply
  • sotoa - Friday, April 03, 2009 - link

    Long time reader, first time post.
    I really liked the background story and appreciate how Anand delves deep into the the SSD's (as well as other products in other articles).

    Thanks for looking out for the little guy!
    Keep up the great work!
    Reply
  • siliq - Wednesday, April 01, 2009 - link

    With Anand's excellent article, it's clear that the sequential read/write thoroughput doesn't matter so much - all SSDs, even the notorious JMicron series, can do a good job on that metric. What is relevant to our daily use is the random write rate. Latencies and IOs/second are the most important metric in the realm of SSD.

    Based on that, I would suggest Anand (and other Tech reporters) to include a real world test of evaluating the Random Write performance for SSD. Because current real-world tests: booting windows, loading games, rendering 3D, etc. they focus on the random read. However, measuring how long it takes to install Windows, Microsoft Visual Studio, or a 4-GB PC Game would thoroughly test the Random Write / Latency performance. I think this is a good complementary of our current testing methodology
    Reply
  • Sabresiberian - Tuesday, March 31, 2009 - link

    Just wanted to add my thanks to Anand for this article in particular and for the quality work he has done over the years; I am so grateful for Anandtech's quality and information and the fact that it has been maintained! Reply
  • Sabresiberian - Tuesday, March 31, 2009 - link

    Oops didn't proof, sorry about the misspell Anand! Reply
  • hongmingc - Saturday, March 28, 2009 - link

    Anand, This is a great Article and a good story too.
    The OCZ story caught my attention that a quick firmware upgrade make a big improvement. From my understanding that SSD system designers try to trade off Space, Speed, and Durability (Also SSD :)) due the nature of NAND flash.
    We can clearly see the trade off of Space and Speed when SSD is getting more full the slower the speed (This is due to out-of-place write to increase the write operation and a block reclaim routine). However, Speed is also sacrificed to achieve the Durability (by doing wear leveling). Remember SLC nand's life time is about 100K write, while MLC nand has only about 10K write. Without considering doing wear leveling to improve the life cycle of the SSD, the firmware can be much simple and easy which will improve the write operation speed quite a bit.
    I echo you that the performance test should reflect user's daily usage which can be small size files write and may not be 80% full.
    However, users may be more concern about the Durability, the life cycle of the SSD.
    Is there such a test? How long will the black box OCZ Vertex live?
    How long will the regular OCZ Vertex live? and How long will the X25 live?
    Reply
  • antcasq - Sunday, April 05, 2009 - link

    This article was excellent, explaining several issues regarding performance.

    It would be great if the next article abou ssd addresses durability and reliability.

    My main concert is the swap partition (Linux) or virtual memory file (Windows). I found an post in another website saying that this is not an issue. Is it true? I find it hard to believe. Maybe in a real world test/scenario the problem will arise.
    http://robert.penz.name/137/no-swap-partition-jour...">http://robert.penz.name/137/no-swap-partition-jour...

    I hope AnandTech can take my concerns into consideration.

    Best regards
    Reply
  • stilz - Friday, March 27, 2009 - link

    This is the first hardware review I've read from start to finish, and the time is well worth the information you've provided.

    Thank you for your honest, professional and knowledgeable work. Also kudos to OCZ, I'll definitely consider the Vertex while making purchases.
    Reply

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