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SanDisk Z400s SSD Review

SanDisk has the exclusive on Silicon Motion's SM2246XT controller. What's more, we got our 128GB Z400s for just $.25/GB. But is this a true low-cost contender, or just a cheap SSD?

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A Closer Look

Every aspect of the Z400s is designed to reduce production costs. The drive itself is made to a level that would be unacceptable by an enthusiast's standards. The enclosure is almost entirely plastic, aside from thin metal inserts for mounting screws. And there isn't a single screw holding the chassis together.

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Again, the Z400s ships in mSATA, M.2 and 2.5-inch form factors. Today we're testing the 2.5-inch 128GB model with a 7mm z-height.

Inside, there's a very small printed circuit board that takes up roughly one-third of the available space. Neither the controller nor the flash benefits from augmented cooling, though that shouldn't be an issue on an entry-level solution.

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This is our lab's first outing with Silicon Motion's SM2246XT, from the same family as the SM2246EN (used in a large number of existing low-cost client SSDs). SanDisk pairs the processor with 15nm MLC NAND. The 128GB drive uses two flash packages with 64GB each. We suspect the 256GB model would simply double the number of packages to four.

Data Type Comparison And SLC Cache

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Compressible and incomprehensible data are handled at the same rate on SanDisk's Z400s. Silicon Motion doesn't use a compression engine that penalizes write performance when working with incompressible data.

Don't let the terms DRAM-less, OEM and low-cost make you think this thing is a total dog. There are worse-performing drives with three-bit-per-cell flash shipping under the guise of low-cost solid-state drives. For instance, we recently reviewed Adata's 120GB SP550, which delivered sustained sequential writes of 66 MB/s with 64KB blocks. 

Sandisk Z400s (256GB)

Sandisk Z400s (128GB)

Sandisk Z400s (64GB)

13 Comments Comment from the forums
  • ZolaIII 24 December 2015 12:33
    Would actually like to see the 240 GB model & dose it catches up at least reasonable with declared write speeds.

    Whole topic is a dead fish until we see first implementation next year that will use 3D XPoint RAM instead of DRAM for caching purposes.
    Reply
  • zodiacfml 24 December 2015 14:43
    Nothing to see here except the OEMs who will probably save more by choosing this drive.
    Reply
  • rmszaphod 24 December 2015 15:51
    Misread.
    Reply
  • Duken4evr 24 December 2015 15:59
    Newegg has Adata 128GB drives on sale for $38. Deal abound out there. OEMs may buy these for cheap so they can advertise their $400 laptop has an SSD, but the rest of us smart shoppers can score deals on better drives for our upgrade purposes.
    Reply
  • Marcus Zettergren 24 December 2015 16:01
    Part of the conclusion just doesn't make sense even though i agree the Evo is so much better.

    As a potential upgrade, the Z400s is a fairly poor prospect, largely because of its price. In terms of value, Samsung's 850 EVO just wrecks every other company's attempt to compete. With the 128GB Z400s at $45 and the 120GB 850 EVO going for $68, we have to recommend Samsung's offering.

    Unless my maths are way off, which it very well could be, the EVO is 62% more/GB. For a gaming disk, the Z400 is just as good as the EVO, and i suspect for a thin ultrabook with a "U" cpu, the cpu will be the bottleneck long before an SSD would be a showstopper.
    Reply
  • photonboy 25 December 2015 06:40
    Marcus Zettergren,
    Gaming performance (which mainly only affects load times) is but one use case scenario. The CPU isn't going to be the bottleneck either, though low-cost notebooks can be limited by the main chipset of the motherboard, though even then it wouldn't be a total bottleneck but could limit performance.

    How the CPU, chipset, and different scenarios work isn't a simple calculation.

    I think this is GREAT to have an offering like this. I know fast SSD's seem important to most people but they way my sister uses her PC she wouldn't know the difference. It would still boot up pretty quick and then she's mostly in an office environment.

    It's a lot faster than an HDD at times, reasonably inexpensive, and won't take several seconds to come out of standby mode like an HDD.
    Reply
  • nekromobo 25 December 2015 10:22
    If we want to push solid-state storage into lower-end systems, the expensive DRAM has to go.

    According to Anandtech this December 2015:

    The average spot price of one 4Gb DDR4 memory chip rated to run at 2133MHz was $2.221 at press time, according to DRAMeXchange,

    So for a DRAM in SSD thats 2.221$ well spend (Ok, maybe it increases cost 4$ but anyway...)
    Make it DDR3 and youll save 50cents.
    Reply
  • CRamseyer 26 December 2015 04:43
    There is a bit more to it than just the physical DRAM. The controller has to have provisions in place for it, the extra design in the PCB, other components to support the DRAM and so on. It all adds up when companies are fighting to find a way to shave off a few Dollars at a time.
    Reply
  • photonboy 26 December 2015 13:08
    17193485 said:
    There is a bit more to it than just the physical DRAM. The controller has to have provisions in place for it, the extra design in the PCB, other components to support the DRAM and so on. It all adds up when companies are fighting to find a way to shave off a few Dollars at a time.

    Exactly.
    Let's do some more meaningful algebra which I'm making up of course but know to be quite possible:
    1) Profit margin of laptop-> $10
    2) Savings on SSD (total) vs faster SSD-> $5

    Profit is DOUBLED!

    Most people will just see that it's an SSD and the capacity on the entry or mid-tier devices this would be aimed for. Saving $5 can make a huge difference in profits since as said they're fighting over scraps a lot of the time.

    Some mobile devices were actually just BREAKING EVEN due to the tight competition and price drops.
    Reply
  • uglyduckling81 28 December 2015 21:47

    1) Profit margin of laptop-> $10
    2) Savings on SSD (total) vs faster SSD-> $5

    Profit is DOUBLED!

    Just tell me again how a $10 profit increased to a $15 profit is double?
    Reply