4K Random Read/Write
We precondition the Micron P400m for 18,000 seconds, or five hours. Every second we are receiving reports on several parameters of the workload performance. We then plot this data to illustrate the drives' descent into steady state.
This chart consists of 36,000 data points. The green dots signify the IOPS during the test, and the light blue (teal) dots are the latency encountered during the test period. We place the latency data in a logarithmic scale to bring it into comparison range. This is a dual-axis chart with the IOPS on the left and the latency on the right. The lines through the data scatter are a moving 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 provide histograms to provide further latency granularity below. This preconditioning slope of performance happens very few times in the lifetime of the device, and we present these test results for the tested device only to confirm the attainment of 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 Micron P400m provides a very tight performance range as it averages 53,847 IOPS at QD256. The Intel DC S3700 delivers an average speed of 64,533 IOPS. The SMART Optimus, with its native SAS connection, provides an average read speed of 93,860 IOPS at QD256.
We observe several dips in performance with the Intel SSD in the QD64 and QD256 range, and one period at QD 32 where the P400m jumps appreciably. These are indicative of the housekeeping routines running in the background.
It is worth noting that the Micron P400m returns back to its normal level of performance quickly, possibly due to the ReCAL algorithms kicking in and steadying performance. The Intel DC S3700 experiences these dips continuously on a steady cadence, as it seems to simply run the garbage collection algorithm at a predetermined time. Micron's approach to intelligent garbage collection routines in observance of the level of I/O requests provides a consistent level of performance.
Garbage collection routines are more pronounced in heavy write workloads. The Micron delivers solid performance with very little variability, and the Intel's latency optimization seems to focus around the garbage collection routines triggering at steady intervals of 90-100 seconds. The SMART Optimus provides the least variability of the three.
The scale of this chart should be taken into consideration, with the Micron P400m and Intel DC S3700 varying only 6,000 IOPS from minimum to maximum, while the Optimus performance is within a few thousand IOPS.
The Micron averages 26,815 IOPS, the Intel DC S3700 averages 36,428 IOPS, and the SMART Optimus averages 43,081 IOPS at QD 256.
The Micron P400m serves 46.9% (3,784,211 I/Os) of requests within the 4-6ms range, and 51% of commands (4,126,898 I/Os) in the 10-20ms range. This higher latency is reflected by the slower write speed of the P400m in comparison to the other two SSDs, but we do not note any large areas spikes or variances in performance.
The power consumption measurements, taken during our precondition run, for the Micron P400m are very good. We can see that it maintains steady power consumption over the course of the precondition run (4.5 hours). The Micron averages 3.5 Watts, in comparison to the Intel at 4.36 Watts and the SMART Optimus at 6.51 Watts. The P400m scores 7,624 IOPS per Watt, the Intel scores 8,336 IOPS per Watt, and the Optimus scored 6,617 IOPS per Watt.