Benchmark Results: 128 KB Sequential Performance
SSD manufacturers often want to stress random performance because they clearly decimate conventional hard drives. Sequential performance is a little different, but still represents an important aspect of the performance picture.
But how pervasive is sequential performance for the average user? Take a look at the graph below; it shows the distribution of all the seek distances from one of our traces.
The first thing you'll notice is that there's a preponderance of activity zero sectors away, which means that our trace is made mostly of back-to-back requests, or sequential I/O. If the trace was 100% random, none of the accesses would be zero sectors away.
Intel's 250 GB SSD 510 leads the pack in reads, but the 256 GB 830 follows closely behind. Samsung's sequential write performance, though, is simply impressive. The company's latest SSD unseats the HyperX and Vertex 3 for top billing. Kingston and OCZ both employ SandForce's compression technology to reach that level of performance; Samsung doesn't enjoy the benefit of DuraWrite technology. Instead, the 830 relies on its improved controller and the Toggle-mode NAND that we already know yields the best throughput for its performance.
Don't be completely dissuaded by these lower performance results. They're not new-in-box numbers; they represent steady-state performance, which changes the behavior of the SSD. This is a particularly bad scenario because the testing happens after each drive is filled with incompressible data, but before idle garbage collection is able to help recover performance.
As most of you know, SandForce's architecture is most efficient when it's operating on compressible data. In the real world, that's actually a pretty realistic expectation of what it'd be working with most often, making these results, again, a worst-case situation for the SF-2200-based drives.