Random Read/Write Speed

The four corners of SSD performance are as follows: random read, random write, sequential read and sequential write speed. Random accesses are generally small in size, while sequential accesses tend to be larger and thus we have the four Iometer tests we use in all of our reviews.

Our first test writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random access that you'd see on an OS drive (even this is more stressful than a normal desktop user would see). I perform three concurrent IOs and run the test for 3 minutes. The results reported are in average MB/s over the entire time. We use both standard pseudo randomly generated data for each write as well as fully random data to show you both the maximum and minimum performance offered by SandForce based drives in these tests. The average performance of SF drives will likely be somewhere in between the two values for each drive you see in the graphs. For an understanding of why this matters, read our original SandForce article.

Desktop Iometer—4KB Random Read (4K Aligned)

Random read performance has not been dramatically improved. In fact, the mSATA version actually takes a small hit (~12%).

Desktop Iometer—4KB Random Write (4K Aligned)—8GB LBA Space

Desktop Iometer—4KB Random Write (8GB LBA Space QD=32)

Random write speed, on the other hand, is substantially better. We are still nowhere near SandForce or OCZ Vector numbers but at least the performance is no longer sub-par. The performance also finally scales up as the queue depth increases (at least for the 2.5" model). The scaling could be more aggressive at higher QDs but I'll rather take good low QD performance as that will have a bigger impact in real world performance where most IOs are between QDs of 1 and 5.

Sequential Read/Write Speed

To measure sequential performance I ran a 1 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. The results reported are in average MB/s over the entire test length.

Desktop Iometer—128KB Sequential Read (4K Aligned)

Sequential performance is also very good. Surprisingly the BP4 mSATA is again slower in write performance than the BP3 and compared to the 2.5" BP4, there is quite a big difference.

Desktop Iometer—128KB Sequential Write (4K Aligned)

AS-SSD Incompressible Sequential Performance

The AS-SSD sequential benchmark uses incompressible data for all of its transfers. The result is a pretty big reduction in sequential write speed on SandForce based controllers.

Incompressible Sequential Read Performance—AS-SSD

Incompressible Sequential Write Performance—AS-SSD

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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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