Silverstone MS12 and Yottamaster HC2-C3 USB 3.2 Gen 2x2 20Gbps Enclosures Reviewed

Worst-Case Performance Consistency

Flash-based storage devices tend to slow down in unpredictable ways when subject to a large number of small-sized random writes. Many benchmarks use that scheme to pre-condition devices prior to the actual testing in order to get a worst-case representative number. Fortunately, such workloads are uncommon for direct-attached storage devices, where workloads are largely sequential in nature. Use of SLC caching as well as firmware caps to prevent overheating may cause drop in write speeds when a flash-based DAS device is subject to sustained sequential writes.

Our Sequential Writes Performance Consistency Test configures the device as a raw physical disk (after deleting configured volumes). A fio workload is set up to write sequential data to the raw drive with a block size of 128K and iodepth of 32 to cover 90% of the drive capacity. The internal temperature is recorded at either end of the workload, while the instantaneous write data rate and cumulative total write data amount are recorded at 1-second intervals.

Sequential Writes to 90% Capacity - Performance Consistency
TOP: SilverStone MS12Yottamaster HC2-C3	BOTTOM: Yottamaster HC2-C3SilverStone MS12

The HC2-C3 comes out on top in the sequential write access test, in contrast to what was observed in the AnandTech DAS Suite workloads. While the MS12 managed to maintain impressive temperatures in that transfer set (going only as high as 65C during the course of the testing, compared to the 70C for the HC2-C3), the situations are reversed in the sustained write testing above. The running out of the SLC cache is only evident for a short duration before the SK hynix Gold P31 recovers and sustains performance numbers around 1750 MBps in the HC2-C3 (down from a peak of 1880 MBps). The temperature was 62C at the end of the 8 minutes it took for the test to complete. On the other hand, when used in the MS12, the Gold P31 tries to get back to peak transfer rates occasionally, but comes out with an average of around 1450 MBps after the running out of the SLC cache. That said, it does manage to maintain the 1880 MBps SLC caching speed for a longer duration compared to the HC2-C3. The temperature also ended up at 74C for the MS12.