4K Random Read/Write
We precondition the 12Gb/s HGST Ultrastar SSD800MM for 18,000 seconds, or five hours, receiving reports on several parameters of workload performance every second. We then plot this data to illustrate the drives' descent into steady state.
This chart consists of 36,000 data points. This is a dual-axis chart with the IOPS on the left and the latency on the right. The dark blue dots signify IOPS during the test, and the light blue dots are latency measurements during the test period. We place latency data in a logarithmic scale to bring it into comparison range. The lines through the data scatter are the average during the test. This type of testing presents standard deviation and maximum/minimum I/O in a visual manner.
Note that the IOPS and Latency figures are nearly mirror images of each other. This illustrates the point that high-granularity testing can give our readers a good feel for the latency distribution by viewing IOPS at one-second intervals. This should be in mind when viewing our test results below.
We also provide histograms for further latency granularity. This downward slope of performance happens very few times in the lifetime of the device, typically during the first few hours of use, and we present the precondition results only to confirm steady state convergence.
Each QD for every parameter tested includes 300 data points (five minutes of one second reports) to illustrate the degree of performance variability. The line for each QD represents the average speed reported during the five-minute interval.
4K random speed measurements are an important metric when comparing drive performance, as the hardest type of file access for any storage solution to master is small-file random. One of the most sought-after performance specifications, 4K random performance is a heavily marketed figure.
The HGST SSD800MM tops the chart with an amazing average of 147,429 IOPS at QD256. The Toshiba PX02SMF080 produces an average of 124,224 IOPS at QD256, followed by the SMART Optimus with an average of 100,290 IOPS at QD256 in dual port mode. The Optimus has the tightest read pattern with the least variability, but HGST takes off with 47,000 more IOPS in performance. The SSD800MM really hits its stride with the highest load at QD256.
Garbage collection routines are more pronounced in heavy write workloads, leading to more performance variability.
The HGST SSD800MM leads the test pool with an average of 64,487 IOPS at QD256. The SMART Optimus averages 44,326 IOPS at QD256, the Toshiba 12Gb/s averages 27,165 IOPS at QD256, but significant performance variability muddies the performance picture. The HGST SSD800MM easily wins in this test.
Our write percentage testing illustrates the varying performance of each solution with mixed workloads. The 100% column to the right is a pure write workload of the 4K file size, and 0% represents a pure 4K read workload.
The HGST Ultrastar leads this test with very strong performance across the board in the mixed read/write testing. The PX02SMF080 and the Optimus juggle second place. With the higher-endurance SSD800MH providing 100,000 write IOPS in steady state, this dominating performance gap would be even higher.
The HGST SSD600MM has a very tightly defined latency range with 64.75% (12,460,267 I/O's) landing at 2-4ms, and 33.31% (6,410,093 I/O's) in the 4-6ms range.
We record the power consumption measurements during our precondition run. We calculate the stated average results during the last five minutes of the test, after the device has settled into steady state.
The HGST averages 7.49 Watts, very close with the Optimus with an average of 7.51 Watts. The Toshiba sports significantly lower power consumption with an average of 5.63.
IOPS to Watts measurements are generated from data recorded during our precondition run, and the stated average is from the last five minutes of the test.
The HGST SSD800MM provides a great IOPS-to-Watts ratio of 8,396 IOPS per Watt. This is nearly double the 12Gb/s Toshiba PX02SMF080, which averages 4,843 write IOPS per Watt. The Optimus averages 5,906 write IOPS per Watt.