Toshiba Q Series Pro 512 GB full review

Last year so the Toshiba, the inventor of NAND flash, join the ranks of companies making and selling flash drives to end PC users. At the time we commented on its poor marketing, still stuck with unfathomably long and unwieldy product designations.

Shortly after our review of the Toshiba THNSNH512GCST though, and clearly after the Japanese semiconductor had realised the same problem, it handily renamed the same drive to Toshiba Q Series. Now following up, but not replacing, that drive is the Toshiba Q Series Pro. As the name suggests, its aiming to be the next grade up.

See also: Storage reviews

Available in three capacities of 128, 256 and 512 GB, Toshiba is still taking a different tack to those SSD designers that set aside some NAND flash for over-provisioning to aid long-term performance and endurance. And indeed, Toshiba only offers a 3-year guarantee on even this Pro-branded drive.

Pricing is reasonably keen, although we note that the largest 512 GB-sized version is not readily available from the usual online shops. Looking at the other two capacities though the Q Series Pro can be found for less than 50p per gigabyte.

Little is known about the workings of the SSD, and even the provenance of the controller is uncertain – the earlier non-Pro Q Series was believed to be using a Marvell controller with Toshiba’s own firmware. For this drive the controller is labelled with a Toshiba part number but it could yet be a rebranded Marvell chip. Bucking the trend of most SSDs (with the exception of SandForce-based drives) this may even be a cacheless design, with no additional DRAM to buffer data before writing.

For followers of mobile computing, it may be useful to know that the Toshiba SSDs are still just about the lightest weight available – this model tips the scales at just 53 g, thanks to a thin aluminium case of now-typical 7 mm thickness.


After a turn on the test bench we were left wondering what has changed since last year’s Toshiba THNSNH512GCST/Q Series drive. Starting with the basic sequential drag race, the Q Series Pro returned figures of 553 and 519 MB/s for its reads and writes. Pretty good figures that compare spookily closely to the 554 and 519 MB/s of the standard Q Series. But these are simplistic tests that show little of the minutiae of solid-state performance.

In the CrystalDiskMark test of best sequential, we noted a slight lift in sequential reads with the Pro drive, but at circa 510 MB/s reads and 470 MB/s for writes, we again have the same results.

Single-threaded random read/write numbers were a little different, but skewed in favour of last year’s SSD. The Pro scored around 22 MB/s reads and 78 MB/s writes; the THNSNH512GCST could hit 22 and 90 MB/s, suggesting a little more speed in small-file writing.

Stacked data showed again that Toshiba has elected to tune performance to read tasks, with 379 MB/s 4 kB random reads and 259 MB/s random writes. The previous model was recorded with a little more bias toward reading, namely 384 against 225 MB/s.

In the AS SSD test, the overall score was fractionally ahead with the new Pro-branded Q Series. Delving into the results, we can see that the sum of multi-threaded write operations is slightly higher, now hitting 49 k IOPS against the latest version’s 58 k IOPS. Read IOPS are unchanged at 91.9 k IOPS.

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