IOMeter — Sequential and random performance
IOMeter fuels much of our latest storage test suite, including our sequential and random I/O tests. These tests are run across the full capacity of the drive at two queue depths. The QD1 tests simulate a single thread, while the QD4 results emulate a more demanding desktop workload. For perspective, 87% of the requests in our old DriveBench 2.0 trace of real-world desktop activity have a queue depth of four or less. Clicking the buttons below the graphs switches between results charted at the different queue depths.
Our sequential tests use a relatively large 128KB block size.
The XPG SX930 comes out of the gate with reasonable performance numbers. Its sequential read speeds are solid but unremarkable, roughly in line with OCZ's Arc 100 240GB and Transcend's SSD370 256GB. The Adata drive's write numbers are relatively weaker than its reads, but they still fall within the realm of respectability. The 850 EVO 250GB is only a touch faster, and that's fine company to be in. But let's not forget that 250GB-class MLC drives can be much, much faster: OCZ's Vector 180 250GB posts write speeds almost double those of the XPG SX930's.
Next, we'll turn our attention to performance with 4KB random I/O. The tests below are based on the median of three consecutive three-minute runs. SSDs typically deliver consistent sequential and random read performance over that period, but random write speeds worsen as the drive's overprovisioned area is consumed by incoming writes. We've reported average response times rather than raw throughput, which we think makes sense in the context of system responsiveness.
Random read and write performance doesn't look much different from the sequential results. The SX930's reads are roughly in the middle of the pack. Its write numbers are a bit less compelling, but plenty fast enough in real-world terms. The Adata drive halves the write reponse times of the SSD370, and we found that drive's peformance plenty acceptable.