One size doesn't always fit all, and the continuing evolution of MLC SSDs has led to product segmentation from the large SSD manufacturers. There are now three distinct categories to address varying workloads: read-intensive, mixed-use, and write-intensive. These different categories allow administrators to select SSDs that precisely target their workload to provide the most economical means of addressing performance challenges. These different categories of SSDs are defined primarily by their write speed and endurance specifications.
Micron features one of the most diverse flash product stacks of the enterprise companies. Micron has entry-level SSDs for personal and business use, mission-critical SSDs, and PCIe SSDs in both MLC and SLC flavors. The M500 is the current value choice for light enterprise workloads. Its economical price point provides spacious capacity for those who prioritize price over all other factors. The M500 delivers solid performance and much lower latency than any HDD, but for those in the hunt for an SSD between Micron's flagship P400m and the M500, there hasn't been a choice…until now.
The M500DC rounds out the Micron product stack by providing a SATA 6Gb/s SSD tailored for mixed-use environments. By leveraging many of the same design aspects of the M500, such as L85A 20nm MLC NAND, Micron has also kept the price of the M500DC squarely in the value arena. Micron only charges a slight premium over the M500, but infuses a big boost in performance.
The 2.5-inch M550DC flaunts an astonishing 4k random write speed of 35,000 IOPS for the 480GB capacity we are testing today. This is within the realm of leading flagship 6Gb/s SSDs. Write speed scales with capacity, and the bookend 120 and 800GB capacities provide 23,000 and 24,000 4k random writes, respectively. The remaining capacity point, 240 GB, provides 33,000 IOPS. The random read speed is 63,000 IOPS for the three smaller capacities, and the 800GB model provides a slight boost to 65,000 IOPS.
The random performance of the M500DC is impressive, and there isn't currently an economical enterprise SSD with this performance level. Sequential speed isn't as impressive, with an average write speed ranging from 200 to 375 MB/s and a sequential read speed of 425 MB/s for all capacity points. It does bear mentioning that the percentage of users that purchase SSDs for their sequential performance is small; HDD's offer plenty of performance in that respect. In addition, generic measurements of sequential performance can be misleading. A spoiler: the M500DC provides surprisingly good performance in multi-threaded mixed sequential workloads.
The M500DC offers full-data path protection and die-level data redundancy as part of its comprehensive XPERT feature set, detailed on the following page, and an UBER rating of 1 per 10^15. Power loss protection is handled by tantalum capacitors, and the M500DC features a 2-million-hour MTTF.
With all of the bases covered for performance, and peripheral advantages normally incorporated into flagship-class SSDs, many will wonder what leads Micron to price the M500DC in such economical territory. The difference lies with the endurance; the M500DC only offers two Drive Writes Per Day (DWPD). This is a significantly lower threshold than SSDs destined for the most write-intensive workloads. The standard M500DC lacks encryption features. In many cases, encryption can be problematic for export sales for OEMs and ODMs, so the inclusion of standardized encryption isn't always the best solution for this class of drive. Micron also offers a TCG OPAL 2.0 option for those with encryption requirements.
Micron provides impressive performance at an unbelievably good price point. Let's take a quick look inside.