October 28, 2009, 5:27 PM — 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.