A moment with M.2
The M600 family combines a full line of 2.5" drives with a collection of tiny mSATA and M.2 units. All the mSATA flavors have the same footprint, but the M.2s are available in single-sided 2280 and double-sided 2260 variants of the form factor. Those numbers refer to the width (22 mm) and the length (either 60 or 80 mm) of the "gumstick" circuit board. Here's how the M.2 2280 version of the M600 256GB compares to its 2.5" counterpart:
Awww, isn't it cute?
The mini versions of the M600 are basically the same as the 2.5" drives. However, they only scale up to 512GB, and they all have Dynamic Write Acceleration. According to Micron, SLC caching can convey power efficiency benefits by speeding the write process, allowing the drive to return to a low-power state more quickly. Since the mSATA and M.2 models are mostly meant for notebooks, they all have the feature enabled.
DevSleep support is a pre-requisite for SSDs targeting modern notebooks, so it's no surprise that the M600 supports the ultra-low-power state. The drive also has a built-in throttling mechanism that dials back performance if thermals exceed acceptable limits. Pretty standard stuff.
Despite its fancy form factor, the M600 M.2 uses the same old Serial ATA interface as the rest of the family. It requires an M.2 slot with SATA connectivity, so it won't work with the PCIe-only M.2 implementations on some motherboards. That SATA requirement also precludes the M.2 drive from working in PCIe adapter cards.
Our storage test systems are too old to have M.2 slots, so we couldn't throw the mini M600 256GB into the ring with the rest of the SSDs. We did, however, run a few quick tests on the drive and its 2.5" twin using a newer Gigabyte X99-UD4 motherboard. We also ran the same tests on a handful of comparable Crucial SSDs. All of those drives use slight variations of the same Marvell controller paired with different flash configurations. The M500 and MX100 both employ 16 x 16GB NAND dies, while the M500 has a 32 x 8GB array.
The M.2 and 2.5" versions of M600 256GB shadow each other in these tests. Although the M.2 is technically faster in a few instances, it's only ahead by a smidgen.
Impressively, the M600 keeps up with the M550, which has twice as many NAND dies. The M500 and MX100 lag behind, and they're particularly slow in the sequential write speed test. Dynamic Write Acceleration is evidently quite effective in CrystalDiskMark. Let's bust out our usual benchmarks to see how it fares in a broader range of tests—and against a larger collection of competitors.