Mixed Workloads & Steady State
80 Percent Sequential Mixed Workload
The 480GB SP550 starts to pull away from the smaller SP550s in mixed workloads. The SLC buffer still upsets the sequential test, though with only 20 percent writes the effect is not as noticeable. At low queue depths, we again see a large gap between the higher- and lower-performing SSDs. The 240GB SP550 lands in the middle of the pack, but continues to trail the 850 EVO.
80 Percent Random Mixed Workload
This chart confirms what we've come to expect from the SM2256 with regard to random data. The controller, paired with both SK Hynix and Toshiba A19 TLC, can't compete with many of the other low-cost drives. OCZ's Trion 100, armed with a Toshiba controller similar to the Phison S10, also demonstrates poor performance faced with random data. Cost is the big equalizer here, and we'll talk more about that in the conclusion.
Sequential Steady State
The 480GB SP550 finally hits the top of a chart. On paper, it should be up there in every test. But not even a higher capacity and larger SLC buffer maneuvers the Adata drive past Samsung's market leader in most tests. The 240GB SP550 does fare well in this metric, though.
Random Write Steady State
The preconditioning chart contains too many products to make out the 4KB random steady state separation. We use a second chart, which shows the final 100 seconds, for our analysis instead.
We wouldn't expect any of the low-cost drives on our chart to be good contenders for operation in a RAID array. Most of them demonstrate too much deviation between high and low random write performance. The SP550s, unfortunately, are no different.