When I reviewed MyDigitalSSD's BP3, I have to say I was positively surprised. A relatively unknown manufacturer combined with a Phison controller is not the most promising mix. With SandForce you at least know what to expect but our experience with Phison based SSDs had been very limited and Crucial's v4 definitely didn't build a golden image of Phison as a controller maker, which made me very skeptic about the BP3 when I first got it. Fortunately, MyDigitalSSD proved me wrong. The BP3 turned out to be not the highest performing drive, but rather a very good bang for the buck. It was noticeably cheaper than many other mSATA offerings in the market, which made it an alluring option for value orientated mSATA buyers.

Almost immediately after our BP3 and SMART review went up, MyDigitalSSD told me that the successor to the BP3 was already just around the corner: the BP4. From a hardware standpoint it's very similar to the BP3 and MyDigitalSSD has simply switched from 24nm to 19nm NAND, which is logical given the cost savings of smaller lithography NAND. The heart of BP4 is still the same Phison PS3108 controller but there's been some pretty significant changes in the firmware and MyDigitalSSD has also opted to increase the default over-provisioning from 7% to 12%.

With the BP4, MyDigitalSSD is also trying to be more aggressive in the 2.5" field. There was a 2.5" BP3 but MyDigitalSSD never made much noise about it. I raised my concerns about the retail mSATA market in the BP3 and SMART review, although MyDigitalSSD didn't exactly agree with me and they were very satisfied with their mSATA sales (which is absolutely not a bad thing). Either way, MyDigitalSSD is looking to get out of the niche market and the BP4 is aimed directly at the mainstream market. I have to say I'm quite pleased with this approach because most of the so called budget SSDs are fairly bad, so more competition in that market segment is always welcome. The Samsung SSD 840 has really been the only budget drive without any serious drawbacks.

Controller Phison PS3108
NAND 19nm Toshiba Toggle-Mode MLC
Capacities (GB) 60, 120, 240, 480, 960 30, 60, 120, 240
Sequential Read 560MB/s 560MB/s
Sequential Write 530MB/s 520MB/s
4KB Random Read 50K IOPS 4.4K IOPS
4KB Random Write 80K IOPS 16.1K IOPS

MyDigitalSSD sent us both the 2.5" and mSATA versions of the BP4. As you can see in the table above, there is a fairly big difference in performance between the 2.5" and mSATA version. I'm not sure why the difference is that dramatic but it most likely has to do with the controller design. If your controller is designed for high parallelism, you will only get the best performance when all the channels are used. The decrease in performance with fewer channels depends on how heavily you rely on parallelism but it seems like Phison's PS3108 really needs all eight channels to be populated to achieve high performance. Especially as we move to smaller process nodes, parallelism becomes more and more important because read and program latencies increase at every process node.

Quite surprisingly, there's also a 960GB version of the 2.5" BP4 and unlike the other terabyte-class 2.5" solutions we have seen so far, this isn't just two 480/512GB SSDs in RAID 0 but a "real" 960GB SSD driven by a single controller. I actually have a sample in the house already so a review will be up soon.


The 2.5" BP4 has a total of sixteen NAND packages (16GB per die), eight on each side of the PCB. There's also Powerchip Technology's 512MB DRAM chip as a cache, 120GB and smaller capacities will have 256MB instead. 


The casing is very bare from inside. MyDigitalSSD isn't using any thermal pads to dissipate the heat, although they are rarely necessary in consumer SSDs since the controllers are relatively low power.

As the mSATA form factor only has space for four NAND packages, the highest capacity you can achieve with an 8GB die is still 256GB (which will increase to 512GB once 16GB die becomes available). Our review sample is a very early sample that uses 24nm Toshiba NAND (indicated by the 11th character which is an H, 19nm NAND has and I or J), but all retail units should ship with 19nm NAND. 

MyDigitalSSD also sent me their new mSATA to USB 3.0 adapter. For $30, it's definitely worth it if you happen to have a spare mSATA SSD. ASMedia's ASM1053 is acting as a bridge in the adapter and it features support for SATA 6Gbps, although I was only able to reach speeds of around 150MB/s.


Test System

CPU Intel Core i5-2500K running at 3.3GHz (Turbo and EIST enabled)
Motherboard AsRock Z68 Pro3
Chipset Intel Z68
Chipset Drivers Intel + Intel RST 10.2
Memory G.Skill RipjawsX DDR3-1600 2 x 4GB (9-9-9-24)
Video Card XFX AMD Radeon HD 6850 XXX
(800MHz core clock; 4.2GHz GDDR5 effective)
Video Drivers AMD Catalyst 10.1
Desktop Resolution 1920 x 1080
OS Windows 7 x64


Random & Sequential Performance
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  • Kristian Vättö - Wednesday, April 3, 2013 - link

    Intel 525 is mSATA only, so the scores there are for mSATA version ;)

    It really depends on the firmware and hardware you're using. For example, Intel 525 is actually slightly faster than the 520 or 335, which may be due to newer firmware or higher quality NAND, but Plextor M5M is a bit slower than its 2.5" counterpart. A lot depends on the controller/firmware design and how much that relies on parallelism. SandForce does have a minor advantage there because they write less to the NAND due to compression, so you can get away with less (or slower) NAND.

    The overall problem with mSATA is that there really aren't that many drives available, especially in the retail market. Most drives are OEM only (like Samsung's) so getting them in for testing is harder.
  • jhoff80 - Wednesday, April 3, 2013 - link

    Aaah, right, I got it confused with the 520. My mistake.
  • DanNeely - Wednesday, April 3, 2013 - link

    "Most drives are OEM only (like Samsung's) so getting them in for testing is harder."

    Sounds like you just need to start voiding warranty stickers on review ultrabooks to stick the drives into the benchmark box after taking pictures of what's inside the shell.
  • Kristian Vättö - Wednesday, April 3, 2013 - link

    Two problems with that:

    1. Manufacturers don't usually like laptop review samples to be taken into pieces. Having good connections with manufacturers is one of the most important things in this field, so we can't just do what we wish -- we also have to respect manufacturers' requests. Legally all review samples are property of the sender/manufacturer.

    2. Laptop and SSD reviews aren't done in the same place; in fact I'm not even on the same continent as the others. Thus it's not possible (or worthwhile) to send the SSD to me for testing, especially as most laptops only have a few week review period. On the other hand, Jarred/Dustin/Vivek could test the drive, assuming they have a modern desktop, but I'm not sure if that's worth it because dealing with different setups always represents some potential issues when it comes to consistency and they already have tons of work to do.

    Lets put this in another way: What mSATA SSDs would you like to see tested? I can always ask if the manufacturers can give us review samples, even though the drive may not be available for retail.
  • msahni - Wednesday, April 3, 2013 - link

    Hi there,

    I am contemplating buying mSATA drives 240GB-256GB range. It is really becoming confusing to purchase a drive considering so many different specs.
    My options are
    1) Crucial m4 mSATA 256GB http://www.newegg.com/Product/Product.aspx?Item=N8...

    2) Plextor M5M 256GB http://www.newegg.com/Product/Product.aspx?Item=N8...

    3) Intel SSD 525 240GB http://www.newegg.com/Product/Product.aspx?Item=N8...

    4) Mushkin Enhanced Atlas 240GB http://www.newegg.com/Product/Product.aspx?Item=N8...

    I have not been able to get a head to head comparison of the drives anywhere. Most of the tech spec shootouts are of these drives against SSDs or older models.
    Could you please advise which of these drives in your opinion would be the most eligible buy in a real world consumer scenario..

  • MyDigitalSSD - Thursday, April 4, 2013 - link

    Visit Amazon and search bp4 240gb mSATA there are a few still left in stock. Best deal on one right now.
  • Kristian Vättö - Thursday, April 4, 2013 - link

    I would pick either Crucial or Plextor. The Plextor one is a bit faster and Plextor also has very good reputation when it comes to reliability, although in this case the Crucial is "more proven" as it's been out longer. Both are good choices, so this is a matter of personal preference.
  • LouisPR - Wednesday, April 3, 2013 - link

    Happy to see a review about the BP4. I own it since mid February if I'm not mistaken and it's awesome!
  • Vepsa - Wednesday, April 3, 2013 - link

    I really like the price of $160 for the 240GB drive. Seriously considering getting one now and a second later for RAID0.
  • jamyryals - Wednesday, April 3, 2013 - link

    I got one of the 256GB Samsung 830 SSDs for $160. It was a great price for a drive on sale. I'm very happy to see retail starting at that price for a comparable drive. Time to wait and see what BP4's reliability will be like before I jump in on a nicely priced ~500GB.

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