Plextor M5 Pro (256GB) Review

The M3 Pro was one of the fastest SATA 6Gbps SSDs we have tested and I was certain that the M5 Pro would take the crown since it was supposed to be faster than the M3 Pro. However, even though the M5 Pro is faster than the M3 Pro in all of our synthetic tests, it pretty much breaks even in our Storage suites. That doesn't mean that the M5 Pro is slow by any means, it's simply not much of an upgrade. As the M3 Pro is phased out, the M5 Pro will at least be a suitable replacement. 

The bigger issue is power consumption. One of the main reasons I liked the M3 Pro was its extremely low power consumption. The M5 Pro consumes significantly more power and performance is only slightly better. For desktop users, the increased power consumption should not be an issue but purchasing decisions for notebook drives are often driven by power efficiency. Higher power consumption obviously leads to worse battery life.

Dealing with a new controller is not always easy, though. Plextor has been using Marvell's 9174 controller since the M2 series, so the same controller has been used in five different SSDs. Plextor has had plenty of time to tweak the 9174 firmware and that's clearly visible in the M3 Pro: performance is finely tuned and the firmware is mature. The M5 Pro, on the other hand, is their first product to use the new 9187 controller and firmware. It's also Plextor's first drive to use 19nm Toshiba NAND. Integrating smaller process geometry NAND has always been a performance challenge, it's possible that we're just seeing the outcome of those difficulties. Finally there's the chance that we're simply hitting the limits of what you can get over 6Gbps SATA. The M5 Pro is by no means a slow drive, it's clearly among the fastest we've tested. There's only so much parallelism you can extract from smaller transfers, and at the high end we've been gated by the SATA interface's limitations. 

Despite not breaking any records, the M5 Pro is a good drive. Without any huge increases in performance via firmware updates however, the M5 Pro needs to be competitive on price. The M3 Pro wasn't priced as aggressively as it needed to be, but with the M5 Pro Plextor has another chance.