Agility EX is a high-end SSD for the masses

OCZ touts its latest solid-state disk (SSD) drive, the Agility EX, as the first "truly affordable" single-level cell (SLC) NAND flash-based drive available. With a retail price of $399, it's half the price of Intel's X25-E SLC-based SSD. But paying that kind of money for 60GB still seems a bit out of the average consumer's reach.

Still, OCZ's Agility EX is the least expensive SLC-based SSD on the market, so if you're looking for an uber-reliable performance SSD that can handle high-end gaming applications and other demanding tasks, this drive may be exactly what you've been looking for.

In case you're unfamiliar with the difference between SLC and multi-level cell (MLC) NAND, here's a quick refresh. SLC is generally used for data center applications, while MLC is used for consumer products such as MP3 players and laptop flash drives. SLC stores one bit of data per cell while MLC stores two to four bits per cell. MLC has higher capacity than SLC, but with that greater density comes lower native performance and -- without the use of special software -- a shorter life span. MLC can sustain from 5,000 to 10,000 write/erase cycles throughout its life, while SLC can achieve 100,000 such cycles, or more.

In short, when you buy SLC NAND Flash memory products, you're paying extra for better I/O performance as well as a greater reliability and lifespan.

Examining lifespan and performance

OCZ lists its Agility EX SSD as having a mean time before failure (MTBF) rate of 1.5 million hours, which is comparable to the most reliable hard disk drives on the market. By comparison, Intel's X25-E SSD has a MTBF of 1.2 million hours. However, MTBF isn't necessarily the most accurate way of measuring SSD endurance, given that people use drives for vastly different applications. A far more accurate measurement is write endurance. OCZ claims its Agility EX has 100,000 write/erase cycles, the same as the Intel drive.

Like many higher-end SSDs, the Agility EX's internal architecture includes multiple independent I/O channels, each leading to multiple NAND Flash memory chips, to optimize internal bandwidth. Unlike the Intel X25-E, which has 10 parallel channels, the OCZ drive has just four. Yet it uses those four channels effectively to rival Intel's SSD on data throughput.

OCZ claims its drive can achieve up to 255MB/sec sequential read and 195MB/sec sequential write speeds, as well as a 100MB/sec sustained sequential write speeds. (The write speed is augmented by 64MB of onboard cache -- standard on OCZ's mid- to high-end SSDs.) Those speeds, if they hold true, would rival Intel's high-end X25-E SSD.

The Agility EX also uses the popular Indilinx controller, which offers users a better overall computing experience with faster application loading, snappier data access, shorter boot-ups and longer battery life, according to OCZ.

Testing performance

For a test laptop, I used a Dell Latitude D830 with a 2.4GHz Intel Core 2 Duo processor running Windows XP Professional SP2. I connected the drive using an adapter in my laptop's optical drive bay, then tested it using ATTO Technology's ATTO Disk Benchmark v2.34,and Simpli Software's HD Tach v3.0.4 benchmarking utilities. While I was able to successfully test both read and write performance with the ATTO software, HD Tach had problems properly measuring write performance. So, I only have read performance measurements from that utility.

ATTO's benchmark utility revealed read/write times very close to OCZ's claims: the drive achieved 245MB/sec sequential read and 190MB/sec sequential write time.

The HD Tach benchmarking utility showed a consistent 197.3MB/sec average read speed and a random access time of .1 milliseconds. CPU utilization was an unimpressive 11%.

Next, I copied a 4GB folder consisting of 1,619 files of varying sizes, including text documents, photos and video, from the desktop to the My Documents folder on the C drive. The folder transfer took 1 minutes, 20 seconds -- impressive. I then retested the Intel X25-E SSD with the same folder. The file transfer took 57 seconds, shaving 23 seconds off the Agility's time and showing how those extra parallel channels really help.

In the end, OCZ's Agility EX SSD may be slightly slower than Intel's X25-E SSD, but it's also half the price -- something to consider the next time you're looking for a hyper-fast and very reliable SSD. The only drawback to this drive, other than price, is the lack of capacity. While 60GB may be enough space for many users, anyone with serious gaming or work requirements will easily outgrow that.

SSD strategies

For PC owners, one option would be to use the SSD in the primary drive slot to run the OS and I/O intensive apps, and put a slower, higher-capacity hard disk drive in the expansion slot as storage and for slower apps. (You'll need an adapter to fit the 2.5-inch drive into the 3.5-inch drive slots typically used in desktop computers.) Laptop owners could use the SSD as a primary drive and then use a drive adapter in the optical drive slot for a secondary hard disk drive.

SSD drives have come a long way in a short time: capacities have grown while prices dropped. They're still much more expensive than traditional hard drives on a per-gigabyte basis; that's especially true for SLC models like the Intel X25-E and OCZ's Agility EX. For the time being, they remain something of a niche product that appeals to a small, but growing, fan base.

For SD users looking for Intel speed at OCZ prices, the Agility EX should more than fit the bill.

This story, "Agility EX is a high-end SSD for the masses" was originally published by Computerworld.

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