Final Words

The Crucial BX200 comes in last place as often as not. The Crucial BX300 doesn't entirely reverse that, but it still provides one of the biggest generational jumps the SSD market has seen. Micron has learned from their mistakes with the BX200 and produced a worthy successor to the BX100. With the MX300 doing so well as a mainstream SSD with entry-level pricing, the focus of the BX line has shifted from simply being the cheaper option to being the drive designed specifically for the smaller capacities demanded by cost-conscious consumers.

Micron's large 384Gb 3D TLC die is ill-suited to making small SSDs, as 120-128GB SSDs end up only having 3 NAND chips on a four-channel controller, and even at larger capacities the flash is not well balanced across the controller channels. For the next generation of 3D NAND, Micron is addressing this issue by manufacturing both a large 512Gb die and a smaller 256Gb die. Since that 64-layer 3D NAND is still ramping up to full production, Micron has chosen for the BX300 to use their 256Gb 3D MLC that allows for a small SSD to be reasonably fast and free of the downsides of the TLC NAND that dominates the entry-level SSD market.

It's a bit of a puzzle how Micron can afford to sell an MLC SSD for less than their TLC SSD without making serious compromises elsewhere like using a DRAMless controller. But as long as they're willing to sell the BX300 at these prices, it's a great product.

The BX300 only has a few notable weaknesses. Micron's 32L 3D NAND is unusually power-hungry during sequential reads, despite being otherwise quite efficient. This also affects random reads to some extent. The BX300's peak performance is on average slightly below top-tier SATA drives like Samsung's 850 PRO and EVO and the Intel 545s, and it is outperformed by other 3D TLC drives like the MX300 and ADATA SU800 when they're able to make good use of their SLC caches. But this is offset by how well the BX300 retains its performance under heavier workloads and when operating with a nearly-full drive. In that respect, it has a significant advantage over the Crucial MX300.

  120-128GB 240-275GB 480-525GB 960-1050GB 2TB
Crucial BX300 $59.99 (50¢/GB) $89.99 (38¢/GB) $149.99 (31¢/GB)    
Crucial MX300   $99.99 (40¢/GB) $159.99 (32¢/GB) $289.99 (29¢/GB) $549.00 (27¢/GB)
ADATA SU800 $56.68 (44¢/GB) $91.99 (36¢/GB) $168.58 (33¢/GB) $265.00 (26¢/GB)  
ADATA SU900   $108.99 (43¢/GB) $197.80 (39¢/GB)    
ADATA XPG SX950   $109.99 (46¢/GB) $214.99 (45¢/GB)    
Intel SSD 545s   $99.99 (39¢/GB) $169.99 (33¢/GB)    
Samsung 850 PRO   $114.99 (45¢/GB) $212.19 (41¢/GB) $420.99 (41¢/GB) $897.99 (44¢/GB)
Samsung 850 EVO   $89.99 (36¢/GB) $174.75 (35¢/GB) $299.99 (30¢/GB) $715.00 (36¢/GB)

The Samsung 850 EVO is available with very competitive pricing at the moment, shutting many drives using Micron 32L 3D NAND out of the market. The MSRP of the 480GB BX300 we tested is low enough to beat basically everything on a price per GB basis, and is far enough below the Samsung 850 EVO that it isn't an automatic decision to get the Samsung instead. The 240GB BX300 will debut with the same price as the 250GB Samsung 850 EVO, making the Samsung the better option for now.

The smallest capacity of the Crucial BX300 may prove to be the most popular and most competitive. There are other 120GB drives on the market that are priced a bit lower, but the BX300 has the advantage that it uses 3D MLC NAND, doesn't use a DRAMless controller and uses all four NAND channels on its controller. The 120GB BX300 will be slower than the 480GB model we tested, but it will retain the general characteristic of performing almost as well when it is full as when empty. This is far more important at such small capacities. The 120GB BX300 also benefits from lack of competition from Samsung: the planar TLC-based 750 EVO is not available at competitive prices and the 120GB 850 EVO and 128GB 850 PRO were discontinued when Samsung moved from 32L 3D NAND to 48L 3D NAND.

Power Management
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  • MrSpadge - Tuesday, August 29, 2017 - link

    A budget drive with budget price, without any real weakness - well done!
  • nwarawa - Tuesday, August 29, 2017 - link

    Does this thing still have partial power loss protection? I don't see much in the way of capacitors in the images, at least compared to the M500 up to the MX300
  • Ryan Smith - Wednesday, August 30, 2017 - link

    No, it does not. The BX series always omits that feature.
  • nwarawa - Wednesday, August 30, 2017 - link

    "The BX series always omits that feature."

    Incorrect. The BX100 most definitely did. I even confirmed with Crucial themselves.
  • Samus - Sunday, September 3, 2017 - link

    BX100 PCB: http://www.storagereview.com/images/StorageReview-...

    No power loss protection.

    BX series has never offered it. If Micron/Crucial said otherwise, they lied.
  • Samus - Sunday, September 3, 2017 - link

    Here is a high-res shot from AT: http://images.anandtech.com/doci/9144/IMG_2266.jpg

    Kristian seems to believe in that review there are enough caps to drive 8 NAND dies, a piece of 1.35v DDR3 DRAM, and the SMI controller, for 200us.

    As an engineer, without even measuring the capacitance of the tiny inlays of that PCB, it's visually clear this is physically impossible. Just comparing to the PCB of the MX100 which has a dedicated PLP circuit and rows of caps, no matter how much power efficiency the BX100 design has over the MX100, the level of PLP is going to be entirely different, which leads me to this thread:

    This thread has a good definition of "power loss protection" on the BX100: http://forums.crucial.com/t5/Crucial-SSDs/Crucial-...

    Basically, it's discussed that about 2-4MB of the indirection table cache (which is write-thru to the NAND by design) can be protected by the design. In other words, insignificant and irrelevant. This is why PLP was never marketed for the BX100. It's useless. Most non-enterprise implementations are.
  • nwarawa - Tuesday, September 12, 2017 - link

    I wouldn't call partial PLP "useless". Old SSDs wouldn't just lose SOME data. They would often lose ALL data. It would be nice to see an updated version of this test from years ago:

    http://lkcl.net/reports/ssd_analysis.html

    The M4 didn't have the partial PLP, so it would be interesting to see how much of an improvement the M500 with it's partial PLP made. For that matter, some Phison S10 drives and Samsung's last few years of models mention some form of firmware based PLP... so how effective are they?

    Anyone want to start a GoFundMe for this guy to run some updated tests?
  • nwarawa - Tuesday, September 12, 2017 - link

    Update: I reached out to lkcl to see if he's interested in continuing the testing, and if GoFundMe would work for him. I said I would chip in $10-$20 to see some updated test results. Anyone else interested in these tests?
  • nwarawa - Tuesday, September 12, 2017 - link

    Samus, you didn't read carefully enough. It's not whether or not it has FULL power loss protection, but PARTIAL power loss protection. You can read anandtech's review of the BX100 for more information on what that entails. The very link you posted shows the little capacitors that are sufficient for the PARTIAL power loss protection. The reason this was even brought up is that there seem to be fewer of those capacitors on the BX300, which raised doubt as to if the feature was still included. I was just in a convo with Crucial directly, and they confirmed that the BX300 does indeed still have partial PLP.
  • FunBunny2 - Tuesday, August 29, 2017 - link

    when 3D NAND was first proposed, durability was supposed to improve because such devices could/would be built on larger nm nodes. has that actually happened? what node(s) are being used for 32/64L?

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