Iometer is a great tool for helping us isolate the behavior of storage devices in very specific cases. But simply running 4 KB blocks of random data or 128 KB chunks of information sequentially through a drive doesn't give us a true sense of performance in a real-world environment. And that's because most real-world workloads aren't nearly as single-dimensional.
So, we also have a couple of real-world file transfer tests, both of which are indicative of write performance as we move information off of a 240 GB Vertex 3 and onto each of these mSATA-based SSDs.
The first test involves one large media file, which is incompressible due to its already-encoded container. It might surprise you to see so much differentiation between the various drives. However, at the top end, Crucial's m4 isn't affected by the type of data we're moving. And, at the bottom, Intel's SSD 310 only populates five of its controller's 10 available channels, helping explain why it doesn't fare as well.
In fact, we can do a bit of math to figure out just how well each of these SSDs matches up to its rated specifications. Intel claims the SSD 310 80 GB can sustain 70 MB/s sequential writes. We show it doing 79 MB/s. Crucial says the 256 GB m4 should be able to write at up to 260 MB/s. We have it pegged at 244 MB/s. Overall, these numbers look pretty darned close.
So yes, while the responsiveness of an SSD is universally better than what you get from a hard drive, there can be some pretty substantial differences in performance when it comes to moving around lots of information.
Here, we're writing a large folder of files that blend random and sequential accesses. Much of this data is already compressed into large files by Blizzard, so we're not sure how much more SandForce's DuraWrite technology can do to improve performance.
Now we see Intel's SSD 310 doing 107 MB/s, while Crucial's m4 smokes along at 340 MB/s. Both of those figures are in excess of what each vendor rates its product for. However, we ran each drive twice to be sure they were correct and saw consistent results within four seconds from one transfer to the next.
Notable yet again is how much worse the 60/64 GB models do compared to the 120/128 and 240/256 GB drives. That information is particularly important as we come up with some general recommendations on the next page.