Our IOMeter workload features a ramping number of concurrent I/O requests. Most desktop systems will only have a few requests in flight at any given time (87% of DriveBench 2.0 requests have a queue depth of four or less). We've extended our scaling up to 32 concurrent requests to reach the depth of the Native Command Queuing pipeline associated with the Serial ATA specification. Ramping up the number of requests also gives us a sense of how the drives might perform in more demanding enterprise environments.
We run our IOMeter test using the fully randomized data pattern, which presents a particular challenge for SandForce's write compression scheme. We'd rather measure SSD performance in this worst-case scenario than using easily compressible data.
There's too much data to show clearly on a single graph, so we've split the results. You can compare the BX100 and MX200 to the competition by clicking the buttons below each graph.
Instead of presenting the results of multiple access patterns, we're concentrating on IOMeter's database test. This access pattern has a mix of read and write requests, and it's similar to the file server and workstation tests. The results for these three access patterns are usually pretty similar. We also run IOMeter's web server access pattern as part of our standard suite of tests, but it's made up exclusively of read requests, so the results aren't as applicable to real-world scenarios. Our own web servers log a fair amount of writes, for example.
The BX100 250GB and 500GB are evenly matched in IOMeter. The MX200 250GB delivers slightly more IOps than those drives across our escalating load, while the 500GB leaves them in the dust. Even the BX100s compare favorably to Crucial's older SSDs, especially the MX100 256GB.
Versus the rest of the field, the BX100s are middle-of-the-pack performers. That's pretty good considering their pricing. With few exceptions, the only drives that score higher cost substantially more.
Even without a bargain-basement sticker on its side, the MX200 500GB still looks strong. It has among the highest I/O rates at the low queue depths typical of desktop workloads. The 250GB version turns in a respectable overall performance, too, but it's clearly a step behind.
Before timing a couple of real-world applications, we first have to load the OS. We can measure how long that takes by checking the Windows 7 boot duration using the operating system's performance-monitoring tools. This is actually the first test in which we're booting Windows off each drive; up until this point, our testing has been hosted by an OS housed on a separate system drive.
Level load times
Modern games lack built-in timing tests to measure level loads, so we busted out a stopwatch with a couple of titles.
All the SATA SSDs we've tested over the past few years have been within about a second of each other in these tests. I'm hopeful our new load-time tests—and PCIe SSDs—can tease out more meaningful differences. Stay tuned.
We tested power consumption under load with IOMeter's workstation access pattern chewing through 32 concurrent I/O requests. Idle power consumption was probed one minute after processing Windows 7's idle tasks on an empty desktop.
Crucial's new drives are relatively power-efficient. They consume less juice at idle than the company's older models, and the BX100s are especially frugal under load. That drive's four-channel controller probably consumes less power than the eight-channel chip in the MX200.
So ends our performance analysis. If you're curious about the other SSDs in this review or about how we conduct our testing, hit up the methods section on the next page. Otherwise, feel free to skip ahead to the conclusion.