Crucial M550 1 TB full review

Crucial M550

This year’s new model of Crucial’s 2.5in SATA solid-state drive is a relatively minor revision to 2013’s M500 ( The M550 is listed as using 20nm MLC NAND flash again, sourced in-house of course, and there’s still a Marvell controller in charge, this time a Marvell 88SS9189, which must be a revised ‘9187 used in the M500. We asked suppliers to submit the largest drive they could, since larger capacities are more likely to return the best results, but only Crucial acceded with its first 1TB drive. Also see: what's the best SSD

Last year’s M500 was available as a 960GB version, and while it was based on 1024GB of NAND flash, it kept more in reserve for over-provisioning. This helps maintain drive health and longevity, and is useful for preventing significant slow-downs when an SSD is kept under worst-case continual write operation. Now Crucial has opened up its largest SSD to make it truly a terabyte in capacity. While £374 is still expensive, in gigabyte-per-pound terms, it’s staggeringly cheap for a high-performance SSD. At the time of going to press, Amazon was selling the 1TB Crucial M550 for £350, a figure of just 35p per gigabyte. That’s half the price of Intel’s latest 730 Series.

Given the cakewalk test of ATTO Disk Benchmark, the Crucial M550’s highest read speeds were 563MB/s using 512kB data. But as you may expect, like all current solid-state drives it can’t maintain this speed with smaller data chunks. From 256- to 8192kB data, the M550 could keep to its trademark 550MB/s pace; but by 128kB its read speed had fallen to sub-500MB/s figures, finally settling at 21MB/s with the benchmark’s smallest 0.5kB data files.

In CrystalDiskMark, the highest numbers we saw were 478- and 464MB/s for compressible read and write sequential transfers; that already shows a lift in write performance over the M500’s scores.

Small-file operations have benefited on the M550. Single-threaded 4kB writes were at around the 100MB/s mark for the M550; and around 30MB/s for reads. But multithreaded transfers broke the nominal 100 IOPS ceiling for 4kB random reads, at 100k IOPS, with writes not very far behind at 91.7k IOPS. In the AS SSD benchmark, a nominal overall score of 1096 points was the highest tested.

Crucial’s new M550 has significantly pushed up performance. Most importantly, this new model signposts the trend in falling SSD prices, bringing potentially huge capacities within affordable reach.

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