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Sustained and scaling I/O rates
Our sustained IOMeter test hammers drives with 4KB random writes for 30 minutes straight. It uses a queue depth of 32, a setting which should result in higher speeds that saturate each drive's overprovisioned area more quickly. This lengthy—and heavy—workload isn't indicative of typical PC use, but it provides a sense of how the drives react when they're pushed to the brink.

We're reporting IOps rather than response times for these tests. Click the buttons below the graph to switch between SSDs.

To show the data in a slightly different light, we've graphed the peak random-write rate and the average, steady-state speed over the last minute of the test.

Again, nothing particularly noteworthy here. The XPG SX930 holds on to its peak about as long as any of the other 250GB-class drives in the dataset. The peak speed over our testing period is roughly on par with those drives, too. The steady-state speed is no different, falling in between the higher speed of the 850 EVO 250GB and the less-inspired performance of the SSD370 256GB. OCZ's 240GB drives still blow all other contenders out of the water in this test.

Our final IOMeter test examines performance scaling across a broad range of queue depths. We ramp all the way up to a queue depth of 128. Don't expect AHCI-based drives to scale past 32, though—that's the maximum depth of their native command queues.

For this test, we use a database access pattern comprising 66% reads and 33% writes, all of which are random. The test runs after 30 minutes of continuous random writes that put the drives in a simulated used state. Click the buttons below the graph to switch between the different drives. And note that the P3700 plot uses a much larger scale.

The XPG SX930 exhibits no signs of scaling, which is par for the course with the average consumer SATA drive. We won't hold those results against it. As a mostly academic exercise, we'll plot the SX930's results against similar drives to see how the scaling behavior differs.

Not a terribly fascinating result. The XPG SX930's flatlining resembles that of the SSD370, just at a somewhat higher IOps. The 850 EVO 250GB scales at least a little bit, and the Arc 100 (special flower that it is) scales very well.

Read on for the next part of our benchmark suite, which does away with synthetics in favor of real-world performance tests.