Crucial m4 Features & Design

Crucial claims the m4 can achieve read speeds of up to 415MB/s, which is 17% higher than the C300's quoted figures. Write speeds vary between models with the 64GB iteration starting at 95MB/s, followed by the 128GB at 175MB/s, while the 256GB and 512GB versions tout a write throughput of 260MB/s. Compared to the C300, the m4's write speeds are faster by 27%, 25% and 20%, respectively.

Crucial's new drive utilizes the Marvell 88SS9174 controller along with a large Micron 256MB cache to improve small write performance and eliminate any 'stuttering' issues. This has effectively been doubled from the C300's 128MB cache, so we're curious to see if small writes are noticeably improved.

The m4's flash NAND memory is made by Micron, which unsurprising considering Micron owns Crucial. Our 256GB review unit is equipped with 16x16GB 25nm chips (29D128G08CFAAB) and feature Micron's high-speed ONFI 2.1 NAND interface for 166 MT/s with 512-byte industry standard sector size.

Crucial says its m4 series has a MTBF (Mean Time Between Failures) of 1.2 million hours, which is somewhat more conservative of an estimate than the ~1.5 million hours you'll find on most other SSDs. To accompany the usual MTBF figure, Crucial also provides a drive endurance rating for each model.

The 64GB m4 is supposedly good for 36TB of data, while the larger models have a rating of 72TB. While that might not sound too impressive, 72TB breaks down to an average of 40GB per day for five years, which is quite a bit for standard use. Besides, the m4 will be ancient history in five years anyway.

In terms of physical durability, Crucial claims that the m4 offers a shock resistance of 1500G, and that's pretty typical among competing flash products. The company's new drives can also operate reliably at temperatures of up to 70 degrees Celsius and will survive 85 degrees when non-operational.

Like all SSDs, the m4 cites very low power consumption figures. At idle, all four models use less than 100mW. When active, the 64GB and 128GB versions consume just 150mW, while the 256GB and 512GB models have a rating of 160mW and 280mW – the latter of which is still exceptionally low.

The m4 series measures 100.5 x 69.85 x 9.50mm and weighs 75 grams. The drives are compatible with both laptops and desktops, though you'll need an adapter if your chassis doesn't have a 2.5" bay. They'll also work in RAID if you buy more than one and are backed by a limited three-year warranty.