Plextor M6 PRO 256GB Review

Performance Analysis

Peak sequential performance is close to the stated specifications. We saw a maximum of 537MB/sec for read speeds, where it's among the best performers. It also achieves 491MB/sec write speeds, which is obviously fast, but still a little behind the very best SSDs that are 20-30MB/sec faster.

Single queue depth random reads are very good, though the Samsung SSDs to retain a small lead here. However, write performance is disappointing, and the M6 Pro is last in both tests. This is a shame, especially as we've drives using the same NAND do exceptionally well here, which suggests that the issue is related to the controller and/or firmware. At high queue depths, random reads are again strong, and the M6 Pro leads the way in CrystalDiskMark with 410MB/sec. High queue depth writes are thankfully much more promising than single ones, and while the M6 Pro isn't a chart leader, it's never more than 15MB/sec off the top spot.


Both results in PCMark 7 are excellent – only the mighty Samsung SSD 850 Pro and the Toshiba HG6 are faster, and both are more expensive. The SSD also responds well to a Windows installation, giving us the fifth best start up time so far.

The Iometer mixed workloads are very demanding but also relevant at this higher end of the SSD market. The M6 Pro does excellent in the database workload, beating the OCZ Vector 150 and coming a close second overall. It isn't as strong in the file server workload, and even less so in the workstation one, but in both tests the average IOPS figure is still very respectable, and the M6 Pro also holds its own in the sustained battery of random read operations in the web server workload.

Steady state performance, sadly, is not a strong point for the M6 Pro. As the M6 Pro becmes full, performance degrades at a higher rate than the other drives of the same or similar capacity, as indicated by the sharper curves at the start of both charts. Performance also levels off at a significantly lower point than with the AMD Radeon R7 SSD and the OCZ Arc 100. Therefore, if you're going to be using your SSD at or close to full capacity, you may notice the occasional slowdown in everyday tasks, and sustained workloads will be slower than it would be with some of its competition.

PlexTurbo

RAM caching technologies are very dependent on the data you use and your own access patterns, so reliable results and conclusions are hard to draw. However, we enabled PlexTurbo on the M6 Pro and, using AS SSD, faced it off against the Samsung SSD 850 Pro with RAPID Mode enabled, using the latest software and firmware in both cases.


As you can see, sequential performance is clearly stronger with the Samsung SSD, while random performance seems to favour Plextor. In either case, we can see little reason not to enable such technologies.

Conclusion

All considered, the M6 Pro is a pretty good drive. The low performance with single queue depth writes is a shame, but arguably you shouldn't be shopping for drives this expensive if they're the sort of workloads you're concerned about. The steady state performance and I/O consistency is of more concern, however, and we suggest manually overprovisioning the drive so that it always has some additional spare area to work with. Otherwise, however, it handles our test workloads very well, and is a well rounded SSD. The addition of PlexTurbo is great too, though it's unfortunate not to see any more advanced encryption or some basic hardware-based power loss protection. Nevertheless, if you don't quite need the performance of the SSD 850 Pro or your budget can't stretch to it, this is a very viable option in its stead.