4K Random Read/Write
We precondition the Seagate 1200 for 10,800 seconds, or three hours, receiving reports on several parameters of workload performance every second. We then plot this data to illustrate the drive's descent into steady state.
This chart consists of 18,000 data points. This is a dual-axis chart with the IOPS on the left, and the latency on the right. The red dots signify IOPS during the test, and the grey 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 that high-granularity testing can give our readers a good feel for latency distribution by viewing IOPS at one-second intervals. This should be kept in mind when viewing our test results below.
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 tested includes 300 data points (five minutes of one second reports) to illustrate 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 Seagate 1200 averages 104,801 IOPS with a 4K random read workload at QD256, while the Toshiba PX02SMF averages an impressive 124,534 IOPS.
Both SSDs provide the best performance to latency ratio at QD128.
Garbage collection routines are more pronounced in heavy write workloads. This leads to more variability in performance. The Seagate 1200 provides an impressive 42,609 IOPS at QD256, with the Toshiba trailing at 28,307 IOPS.
The 1200 provides a much tighter latency distribution than the PX02SMF while under a heavy 4K write workload.
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 Seagate features a lower performance envelope from 0-70%, but the extensive variability of the Toshiba muddies the water.
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 1200 averages 3.94 Watts during the measurement window, and the Toshiba provides a slightly lower average of 4.30 Watts.
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 1200 bears the fruits of a focus on efficiency with an average of 9,509 IOPS per Watt, while the Toshiba averages 4,835. It is important to note the IOPS per Watts set forth in the specifications of both drives is with read activity. We measure IOPS per Watt with write activity.