Mixed Random Performance

Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.

The Seagate BarraCuda fares poorly on the mixed random I/O test, as do the other Phison S10 drives, even the PNY CS2211 with MLC NAND. The Plextor M8V is the next slowest drive with a mainstream controller, so it appears that the poor performance here from the Seagate BarraCuda is at least partly due to the NAND and is not just due to the Phison S10 controller.

Most mainstream SATA drives in this capacity class average around 1.5-1.6W during this test, so the efficiency rankings largely mirror the performance rankings. That leaves the BarraCuda again near the bottom of the chart.

The fastest drives on this test are the ones that avoid performance drops when writes are added to the mix and instead steadily gain performance as the test progresses. The Seagate BarraCuda doesn't pull that off, with performance that drops when writes are first added to the mix and doesn't recover until near the end of the test when the workload is almost entirely writes.

Mixed Sequential Performance

Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.

The Seagate BarraCuda had great sequential read performance and competitive sequential write performance, but it doesn't handle mixed sequential workloads all that well. As with the mixed random I/O test, the Phison S10 drives are all clustered at the bottom of the chart along with the DRAMless SSDs, while the other mainstream TLC SSDs offer at least 26% higher overall performance—and that comes from the Plextor M8V that uses the same Toshiba 3D TLC as the BarraCuda.

The BarraCuda is again one of the most power-hungry drives, surpassed only by the Phison S10 SSDs that use planar NAND, so it earns one of the worst efficiency scores. The slow DRAMless SSDs at least manage to use far less power during this test, so they end up with pretty good efficiency scores.

The BarraCuda starts off with great sequential read performance, but as soon as writes are added to the mix, throughput plummets. It stays slow through most of the test, recovering only slightly toward the end to deliver just over 300MB/s on pure writes. That final write speed isn't too bad, but most mainstream drives spend the read-heavy half of the test performing well above that level, instead of below 250MB/s.

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