Meet Intel’s Cherryville: 520 Series 240GB SSD Review

Originally developed by Intel, and since given to the open-source community, Iometer (pronounced “eyeawmeter”, like thermometer) is one of the best storage-testing applications available, for a couple of reasons. The first, and primary, is that it’s completely customizable, and if you have a specific workload you need to hit a drive with, you can easily accomplish it here. Also, the program delivers results in IOPS (input/output operations per second), a common metric used in enterprise and server environments.

The level of customization cannot be understated. Aside from choosing the obvious figures, like chunk sizes, you can choose the percentage of the time that each respective chunk size will be used in a given test. You can also alter the percentages for read and write, and also how often either the reads or writes will be random (as opposed to sequential). I’m just touching the surface here, but what’s most important is that we’re able to deliver a consistent test on all of our drives, which increases the accuracy in our results.

Because of the level of control Iometer offers, we’ve created profiles for three of the most popular workloads out there: Database, File Server and Workstation. Database uses chunk sizes of 8KB, with 67% read, along with 100% random coverage. File Server is the more robust of the group, as it features chunk sizes ranging from 512B to 64KB, in varying levels of access, but again with 100% random coverage. Lastly, Workstation focuses on 8KB chunks with 80% read and 80% random coverage.

Because these profiles aren’t easily found on the Web, with the same being said about the exact structure of each, we’re hosting the software here for those who want to benchmark their own drives with the exact same profiles we use. That ZIP archive (~3.5MB) includes the application and the three profiles in an .icf file.

Iometer may be a hard program for users to translate into real world performance, but it is one of the few programs that can truly stress the latest models of SSDs now available and illustrate the differences between them, let alone show what they are truly capable of. Any SSD that does well here is capable of the toughest load conditions found in server racks, so suffice to say it can withstand any usage scenario a desktop user might throw at it.

Intel has always targeted its firmware with 4K size IOPS in mind, and in fact this was one of the best features of Intel’s early X25-M controller. However, this was also the Achilles’ heel for the Marvell controller found in the 510 Series. Suffice to say, Intel made sure to capitalize on the SandForce controller’s innate strengths here and did so in spectacular colors. In all three of our simulated workload tests the 520 Series starts to pull away from even the previous best SandForce SSD in these scenarios.

AS SSD

As the name hints, AS SSD is a nifty little program written exclusively for solid-state drives. It can be run on a mechanical hard drive, but be warned what takes a few minutes will require the better part of an hour to complete! This handy tool measures sequential reads and writes in addition to the important 4KB random reads and writes, then ranks the results with a final score for quick comparisons with other SSDs.

In addition to the main test there is a secondary benchmark that simulates the type of data transferred for ISO, Program, and Game files. With version 1.6 a compression benchmark was also added although not utilized here. We selected this program for its precision, ability to generate large file sizes on the fly, and that it is written to bypass Windows 7’s automatic caching system. The tool does not bypass any onboard cache.

4K-Thrd is similar to the 4K test but spawns multiple requests; basically this tests how good the SSD is at handling multiple file actions at once, aka queue depth. Queue depth wasn’t an issue with HDDs as they were generally too slow to handle more than a few simultaneous IOPS at a time, but with SSDs it is important to have a good controller with a high queue depth. Intel officially designed the 520 to handle a full QD32 rating.

The results here speak volumes about Intel’s choice of optimization when designing its firmware for the SandForce controller. Firmware (and to many respects, controllers themselves) can be optimized to give best performance in one of four areas… sequential read or write speed, and random read or write speed. As we mentioned above Intel has clearly chosen to target random 4K write performance with the 520’s firmware. So although the 520 does not set any sequential records, it manages to offer the best 4K performance of any drive in the 4K write test, and does almost as well in the random 4K read. It also ekes out the lead in the access time test in the process.

Given the well-rounded performance, and leading 4K random IOPS performance, it shouldn’t come as any surprise when the 520 still manages to walk away with the highest AS SSD final score of 802. Although the Max IOPS boutique drive offers marginally better read performance, the 520 comes away with much stronger small file write performance.