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Crucial's MX300 SSD reviewed

The MX series enters the third dimension

3D is all the rage these days. Every Hollywood action flick worth its salt gets screened in both two- and three-dimensional formats, VR is pushing hapless early adopters to stumble over unseen living room furniture, and even Intel is encouraging NUC modders to 3D-print custom lids for their tiny little boxes.

Not even the utilitarian storage market is immune to the trend. Akin to how PCIe and NVMe have long been lurking around the corner, 3D NAND flash technologies have been threatening to rewrite the SSD landscape for a long while. But until now, only Samsung has actually released consumer drives featuring vertically stacked cells. The other manufacturers have been content to dribble out mere hints, announcements, and press releases.

Micron has finally cranked that faucet all the way open and taken the wraps off of its first 3D NAND-equipped SSD, the Crucial MX300. Micron's 3D NAND is one of the more recent products of the company's longstanding NAND partnership with Intel. The MX300 boasts the high-end feature list and performance specs we'd expect out of an MX-series drive, but there are couple of major shakeups under the hood. One is obviously the 3D NAND. The other is a more dubious "upgrade." Micron's seen fit to deploy that 3D NAND in a TLC configuration, replacing the MLC we'd grown attached to in the MX100 and MX200.

This isn't the first time that Micron has taken an existing product line and sneaked in an extra bit-per-cell. Not so long ago, we reviewed the newly-TLC-based BX200 and were left unimpressed by its regression in performance versus its well-received predecessor, the BX100. Let's hope that Micron has learned from that experience and has reason enough to gamble the MX series' good name on TLC.

We should take a moment here to talk about what's different about Intel and Micron's 3D NAND. Planar NAND of all sorts has long been based on floating-gate transistors. To create its stacked flash product, Samsung abandoned floating gates and moved to charge-trap flash, the details of which we discussed at length when we first reviewed the 850 series of drives. Intel and Micron were more stubborn, betting their 3D NAND money on the floating-gate horse. While that choice allowed Samsung to take V-NAND to market first, Intel and Micron believe that their combined ability to leverage years of floating-gate infrastructure and expertise will give them an advantage in the long run.

The first generation of this 3D NAND stacks 32 layers into 256-gigabit MLC or 384-gigabit TLC configurations. As we've already noted, the MX300 uses the 384-gigabit TLC stuff. This is remarkable density. Samsung's first-generation V-NAND (also 32-layer) only maxed out at 128Gb in a TLC die. Even Samsung's second-generation, 48-layer stuff only peaks at 256Gb in a TLC die. Intel and Micron have been hinting that the prodigious density of their flash might eventually lead to monster 10TB SSDs in 2.5" form factors.

For today, we'll have to settle for a 750GB drive. This somewhat unusual capacity is a limited-edition flavor of the MX300, but it's the only one available at launch. I'd say that Micron's taking some Founders Edition cues from Nvidia here, but its suggested retail price for the MX300 is actually pretty reasonable at $199.99. Eventually, the product line will be fleshed out with 275GB, 525GB, and 1050GB versions, but Micron isn't ready to release performance ratings for those drives just yet.

Crucial MX300
Capacity Max sequential (MB/s) Max random (IOps)
Read Write Read Write
750GB 530 510 92k 83k

The NAND inside the MX300 is distributed over eight packages, each of which contains two 384Gb 3D NAND dies. We routinely see SSDs which bundle as many as 16 dies into a single package, so those vague promises of 10TB in a 2.5" drive are starting to sound pretty realistic.

Alongside the NAND packages is a fresh face: Marvell's 88SS1074 controller. The Crucial MX series of drives has always been powered by Marvell controllers, but this chip is one of the newer ones in the company's stable. It's been targeted squarely at the burgeoning TLC SSD market, so it's no shock to see that it's been popping up in newer TLC drives like SanDisk's X400 and Plextor's M7V. We haven't gotten our hands on either of those drives yet, so this is the first time we've had the controller in TR's storage labs. It has all the bells and whistles you'd expect a modern SSD controller to have, like support for DevSleep and 256-bit AES hardware encryption acceleration.

In fact, the MX300 meets all the desirable encryption standards: eDrive, IEEE-1667, and TCG Opal 2.0. Another feature worth mentioning is Dynamic Write Acceleration, Micron's implementation of a pseudo-SLC cache (see our M600 review for details). Crucial's warranty covers the MX300 for three years, much like the warranties on the MX100 and MX200 before it. The 750GB drive has a rated lifespan of 220TB total bytes written, but the truly diligent can use the included free copy of Acronis True Image HD to ensure that their precious data outlives both the warranty and the endurance spec.

Now put on your 3D glasses, because it's time for the show.