Results: Tom's Hardware 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 service time 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 service is similar. The operating system asks the storage device for data 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.
Transcend pushes past some of the less attractive drives we've benchmarked to its own spot adjacent to some 180 GB Intel SSDs, the 256 GB m4, and Crucial's newer M500 at 240 GB.
Mean Read Service Time
The other three highlighted drives punish Transcend's SSD340. Clearly, it's just not as good at servicing burst I/O in our trace, though we'd stop short of calling its failure something to worry about. The delta isn't large, and the outcome doesn't fall out of bounds.
The same story is written by this chart, more or less. When it comes to burst write activity, the 256 GB SSD340 registers the same service time as Crucial's 240 GB M500.