Results: Tom's Storage Bench v1.0, Continued
Beyond the average data rate reported on the previous page, there's even more information we can collect from Tom's Hardware's Storage Bench. For instance, mean (average) service times show what responsiveness is like on an average I/O during the trace.
It would be difficult to graph the 10+ million I/Os that make up our test, so looking at the average time to service an I/O makes more sense. For a more nuanced idea of what's transpiring during the trace, we plot mean service times for reads against writes. That way, drives with better latency show up closer to the origin; lower numbers are better.
Write latency is simply the total time it takes an input or output operation to be issued by the host operating system, travel to the storage subsystem, commit to the storage device, and have the drive acknowledge the operation. Read latency is similar. The operating system asks the storage device for data stored in a certain location, the SSD reads that information, and then it's sent to the host. Modern computers are fast and SSDs are zippy, but there's still a significant amount of latency involved in a storage transaction.
The swiftest SSDs show up in the lower-left quadrant of the above plot. Within that rarefied space, the SSD 730 Series shows up where you'd expect it to: forward of the Samsung SSD in write latency, behind OCZ's newest Vector and Vertex dives in both measurements, and ahead of the Extreme IIs in read latency.
When we break out the individual mean service times, we see the SSD 730 from another angle. At the head of the pack are drives armed with Toggle-mode DDR NAND, mostly. The SSD 730 lands ahead of the M500 and its more dense 128 Gb dies, but behind the technologically-enhanced 840 EVOs and OCZ Vertex 450/Vector 150.
Mean write service times for the SSD 730 are good enough to land in seventh place, again behind drives equipped with Toggle-mode DDR NAND (except for the Vertex 450, which utilizes 20 nm synchronous flash). Ten percent behind the new SSD 730 is Intel's 200 GB SSD DC S3700 with half as many dies as the new 480 GB model.