Plextor is one of those OEMs who have quietly been making their way into the SSD market. They don't have an aggressive marketing engine like for example OCZ does. Their drives are not featured on NewEgg's front page or advertised on most technology sites. If you have read our Plextor M3 review, you might remember that I had not even heard of Plextor before they contacted me. Older users may remember the name Plextor from times when optical drives were relevant, but for years Plextor was out of the spotlight because optical drive performance stopped being relevant for the majority of people and Plextor didn't really have any other products. In 2010, Plextor's ship took a new destination and that was the SSD market.

SSD prices have been dropping significantly over the last couple of years. Especially in the last few months, there have been lots of discounts. For example, the 128GB Vertex 4 had suggested retail price of $179 when it was released in April. Right now it's selling for $120 at NewEgg. That's 33% reduction in price in less than four months. Even more extreme example would be Crucial's m4. When it was originally released in April 2011, the 512GB version had a suggested retail price of $1000. Currently the exactly same drive retails for $400 at NewEgg, and there have been sales bringing the price down as low as ~$350.

The drop in prices has also increased consumer interest in SSDs. You no longer need to spend half of your entire PC budget on an SSD large enough to hold more than just your OS. With more buyers looking for SSDs, there is room for more manufacturers as well. SandForce's licensing strategy has allowed pretty much any hardware company to enter the SSD market, the most recent entrant being MSI. While SandForce SSDs are good in performance and are usually competitively priced, they are all more or less the same (Intel's custom firmware enabled SF drives being the exception). In the end, there are very few SSD OEMs that have truly unique SSDs. Unique in this context means that you at least have your own firmware. Intel, Samsung, Micron/Crucial, OCZ, Toshiba, SanDisk and of course Plextor are probably the most known manufacturers with their own firmware and even controller in some cases. These OEMs also happen to be the largest in the channel SSD market, which is no coincidence. 

While Plextor is still far away from gaining Intel or OCZ status in the SSD world, they are on the right path. We were very pleased with Plextor's M3 and M3 Pro when we reviewed them. Performance was great and both drives were backed by a 5-year warranty (more on reliability in a bit). The only real complaint we had was about pricing, which was not necessarily enough competitive to keep up with the constant price drops. Of course, there were sales that brought the M3's price down to the level of other SSDs, but in most cases you still had to pay premium if you wanted a Plextor SSD.

The M5S that we'll be looking at today is all about cutting costs while still providing the same performance and (hopefully) reliability that the M3 and M3 Pro provided. Without further delay, lets start off with a specification table:

Plextor M5S Specifications
Model PX-64M5S PX-128M5S PX-256M5S
Raw NAND Capacity 64GiB 128GiB 256GiB
Usable Capacity 59.6GiB 119.2GiB 238.5GiB
Number of NAND Packages 8 16 16
Number of Die per Package 1 1 2
NAND Micron 25nm synchronous MLC NAND
Controller Marvell 88SS9174-BLD2
Cache 128MB DDR3 256MB DDR3 512MB DDR3
Sequential Read 520MB/s 520MB/s 520MB/s
Sequential Write 90MB/s 200MB/s 390MB/s
4K Random Read 61K IOPS 71K IOPS 73K IOPS
4K Random Write 25K IOPS 51K IOPS 70K IOPS
Warranty 3 years
MSRP $100 $160 $300

The 128GB and 256GB models are nearly identical to the M3 in terms of performance. There are some minor changes but the only notable one is a 30MB/s increase in sequential write speed for the 256GB model. The 64GB model, on the other hand, has gone through some serious performance reshuffling: sequential write has dropped from 175MB/s to 90MB/s and 4K random write from 40K IOPS to 25K IOPS. 

Comparison of NAND Interfaces
  ONFi Toggle-Mode
Manufacturers IMFT (Intel, Micron, Spectec), Hynix Toshiba/SanDisk, Samsung
Version 1.0 2.0 2.x 3.0 1.0 2.0
Max Bandwidth 50MB/s 133MB/s 200MB/s 400MB/s 166MB/s 400MB/s

Plextor couldn't tell us why they switched NAND suppliers for the M5S but I believe it has to do with price and supply. Remember that the M5S is all about cutting costs. Often times compromises have to be made in order to cut costs sufficiently. In this case, the 64GB model has compromised performance while the bigger capacities continue to run at roughly the same speeds.

A Word on Reliability
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  • shodanshok - Wednesday, July 18, 2012 - link

    Hi Kristian,
    thank you for your reply.

    I understand that measuring WA is your "special sauce" (anything to do with SMART 0xE6-0xF1 attributes ? ;)), but the interesting thing is the Plextor was able to minimize WA while, at the same time, maximize idle GC efficiency.

    Other drivers that heavily use GC (eg: Toshiba and previously Indilinx controllers) seems to cause a much higher WA.

    Thank you for these comprehensive review.
  • sheh - Thursday, July 19, 2012 - link


    I have to say, though, that it's difficult to give credence to data that is the result of undisclosed calculations, and not even by the hardware manufacturers.
  • Kristian Vättö - Thursday, July 19, 2012 - link

    The method we use was disclosed by a big SSD manufacturer a few years ago. It does not rely on SMART or power consumption, and it can be run on any drive.

    If we revealed the method we use, we would basically be giving it out to every other site. Tech industry is quite insolent about "stealing" nowadays, getting content from other sites without giving credit seems to be fine by today's standards.

    Also, our method is just one way of estimating worst case write amplification.
  • shodanshok - Thursday, July 19, 2012 - link

    Hi Kristian
    I totally understand your point.

    Thank you for these great reviews ;)
  • sheh - Thursday, July 19, 2012 - link

    I can't say I understand this logic, but so be it. Thanks for replying. :)
  • jwilliams4200 - Sunday, July 22, 2012 - link

    Does it work for Sandforce SSDs? Because I noticed your WA chart does not have any Sandforce SSDs.

    Are you just measuring the fresh out-of-box (or secure erase) write speed with HD Tune, then torturing the drives and then measuring the worst case write speed with HD Tune? Then saying WA = FOB write speed / worst case write speed ?

    If that is what you are doing, then I don't think it is very accurate. Any SSDs that have aggressive background garbage collection could make the "worst case" write speed fluctuate or stabilize at a value that does not reflect the worst case write amplification.
  • Kristian Vättö - Sunday, July 22, 2012 - link

    SandForce drives break the chart, hence I couldn't include any. SandForce drives typically have worst case WA of around 2x, though.

    I still cannot say what our testing methods are. Anand has made the decision that he doesn't want to share the method and I have to respect that. You can email him and ask about our method - I can't share our methods without his permission.

    In the end it's an estimation, nothing more. How accurate, it's hard to say as it will vary depending on usage.
  • jwilliams4200 - Monday, July 23, 2012 - link

    So it is TERRIBLY inaccurate, because Sandforce SSDs actually have worst case write amplification of well over 10, just like other SSDs.

    In that case, I assume I was correct that you are just using ratio of write speeds from HD Tune, but since HD Tune writes highly compressible data, you are getting bogus results for Sandforce SSDs (actually, I should say, even more inaccurate for Sandforce SSDs than for non-Sandforce)

    Anand really needs to reconsider some of his policies. This "secret" test method is just absurd.
  • jwilliams4200 - Wednesday, July 18, 2012 - link

    It all hinges on finding a way of measuring "flash writes", the amount erased/written to flash chips, as opposed to "host writes", which is easy to measure (the amount your computer writes to the SSD).

    Usually you can find or guess which one of the SMART attributes represents flash writes. You can start by doing large sequential writes to the SSD (for which the WA should be close to, but a little over, 1) and monitoring the SMART attributes to see which one changes like it is monitoring flash writes.

    I remember some time ago an anandtech article mentioned another way of doing it. I'm not sure if they are using this method now or not (I have my doubts about the accuracy of the method). It had to do with measuring the power usage and somehow correlating that to how much writing to flash is occurring. The reason I have doubts about the accuracy of the method is that it would require measuring a sort of "baseline" power consumption when writing to the flash, and to get the baseline you would have to control the conditions of the write (for example, doing it write after a secure erase) in order that you can guess/assume what the WA is, so that you will then be able to compute the WA in more complicated conditions based on the "baseline". But that is rather like pulling yourself up by your own bootstraps, so I would not trust the results.

    The first method I described is the way to go, unless the SSD does not have a SMART attribute that measures flash writes.
  • cserwin - Wednesday, July 18, 2012 - link

    I have to say seing the Plextor brand name resurface kindles a warm, happy feeling.

    There was a time when they made the optical drives to have. A Plextor CD-ROM, a 3DFX Voodoo, a 17" Sony Trinitron, IBM Dekstar...

    Good luck, Plextor. Nice to see the old school still kickin.

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