SanDisk X400 SSD Review (512GB)

Targeted towards read-intensive workloads, boot, and logging applications in both servers and mobile computing, the X400 is SanDisk’s top-tier client SATA SSD available in both M.2 and 2.5″ form factors. Based on the marketing material it seems that SanDisk has put a lot of value into this drive, not only with its feature set, but performance and efficiency.

The X400 is the successor to the X300 and X300s models and utilizes their latest sixth-generation TLC NAND flash as well as a 4-channel Marvell controller with their nCache 2.0 architecture to deliver some impressive performance numbers. With DataGuard Client and LDPC error correction code, its endurance is far beyond their previous models. There are even SED SSD SKU’s offering AES 256-bit encryption with TCG Opal 2.0 support, and moreover, it is backed by a 5-year warranty to boot!

SanDisk X400 SSD

In a time when data security is more important than ever and price being king, will all this be enough to be a Top Value contender in the marketplace? Read on to find out!


The SanDisk X400 is a SATA 6Gb/s SSD that comes in 2.5″ 7mm and single sided M.2 2280 form factors. It is currently available in capacities of 128GB ($48.25), 256GB ($79.99), 512GB ($124.99), and 1TB ($239.95). This makes the M.2 variant the world’s thinnest 1TB M.2 product at just 1.5mm thick! Sequential speeds are rated for up to 545 MB/s read and 520 MB/s write. Random read and write performance is listed for up to 95K/75K IOPS. The endurance figures on the X400 SSDs are as follows: 72 TBW (128GB), 80 TBW (256GB), 160 TBW (512GB), 320 TBW, (1TB). In addition, the MTTF rating is 1.75 million hours.

In terms of features, the X400 has DataGuard Client technology and LDPC error correction. This allows the X400 to deliver high reliability and endurance. A dedicated hardware core performs progressive error correction to minimize latency and keep power usage low. The X400 also utilizes nCache 2.0, which is a multi-tiered caching architecture that allows some of the TLC to operate as SLC and thus provide for fast burst and high sustained sequential write speeds.

It also supports TRIM, DevSleep, SMART monitoring, and TCG Opal 2.0 and AES 256-bit encryption. TCG Opal 2.0 and AES 256-bit encryption support is a big plus since it allows customers to have peace of mind knowing their business data is protected, secured and encrypted when used with compatible software. On top of this, there is also Crypto-Erase support, which has the ability to remove all user data in less than a second by deleting all security keys. All this combined leads to the X400’s solid 5-year warranty.

SanDisk X400 SSD Dashboard

SanDisk even has an SSD toolkit software called SanDisk SSD Dashboard, which includes tools for analysis of the SSD (including drive model, capacity, firmware version, and SMART attributes), performance monitoring, over-provisioning, secure and crypto-erase, diagnostics, cloning, and firmware updating capabilities.


SanDisk X400 SSD Front and Back

Our review sample came void of any packaging, therefore we are unable to comment on it. The exterior of the X400, however, is fairly simplistic in style and made of plastic and aluminum. There is a branding sticker on the front with SanDisk’s logo and the model name. On the backside is a SKU sticker with more specifics on the drive such as capacity, serial number, and compliance logos. Overall, the 2.5″ 7mm model measures 100.5mm x 69.85mm x 7mm and can weigh up to 59.7g for the 1TB option. Four screws hold it together.

SanDisk X400 SSD Disassembled SanDisk X400 SSD PCB

Once opened up we can see there is a large thermal pad attached to the PCB almost entirely to help distribute heat. Our 512GB review sample contains just 4 NAND packages and a single DRAM package and controller on blue the very tiny PCB.

SanDisk X400 SSD Controller

The X400 utilizes SanDisk’s 15nm TLC NAND. Each NAND package is 128GB in capacity for a total raw capacity of 512GB, once formatted the end user has 476GB available to them. The controller is made by Marvell, model number 88SS1074. It is a four channel controller that supports a variety of NAND and features such as DevSleep and AES 256-bit encryption are enabled through it. Furthermore, the 512MB DDR3L-1600 Micron DRAM package provides a cache space for the controller.


  1. blank

    Hey Sean-Is this a replacement for the Ultra 2??????
    Would have liked to have seen how large the SLC cache is-guessing around 8GB.

    If you ever get a chance-could you test a Samsung 650.It’s a strange one,it sits
    below the 750 EVO (which is not much more than a 640 EVO) and yet best I can
    tell it’s 3d nand.Perhaps lower binned nand that don’t make 850 spec…………….

    • blank

      No, it is not the Ultra II replacement. The Ultra II is part of their consumer product line. The X400 is part of their client/business product line.

      We will look into the Samsung 650.

  2. blank

    Hi Sean (or anyone:) ), I was about to buy a 512GB X400, but noticed that at, the older X300 series seems to have outperformed the X400 in write speeds by as much as 50%. Can anyone provide any insight?

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