Results: Tom's Hardware Storage Bench, Continued
Service Times
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.
SanDisk's new offerings fall just behind their Extreme II counterparts, albeit by just a few percent.
The 19 nm Toggle-mode flash attached to Marvell's processor is potent, though not enough so to push above the Samsung and clever OCZ drives. Read latency is approximately 10% behind the leaders.
The newest enthusiast-grade SSDs from Samsung and OCZ posses amazing write properties. Compared to drives from a few years ago, the very latest are stupid-quick. And that doesn't just apply to sequential writes, although they're very fast. Rather, we're most impressed by the ability of an SSD to service write I/O with minimal delay. SanDisk's drives are no exception, and the Extreme IIs and X210 handle our trace effortlessly. The X210s are only marginally slower than their client-oriented counterparts.
