Solid-State Drives: Fact or Hype?

Dr. Fujio Masuoka of Toshiba invented the first flash memory in 1984. Four years later, Intel introduced it as a commercial product. In the late 1980s, the Israeli company Msystems, now part of Sandisk, started selling flash storage solutions for the military and aerospace industries; the lack of moving parts made them ideal for ruggedized systems. At that time, 1 megabyte of flash cost several thousand dollars.

Two years ago, when Samsung unveiled its first-generation SSD, the drive had a capacity of 32 gigabytes, sequential read/write speeds of 57 megabytes per second and 32MBps, respectively, and a hefty price tag of about $1,000. In the ensuing two years, the read and write speeds of the top-of-the-line drives increased more than fourfold, while capacities grew from 32GB to 160GB and, more recently, to 256GB. Prices, however, have remained a weak point for SSDs: While multilevel cell technology (MLC) brings relatively low-end parts’ prices down (64GB MLC parts can be found for less than $200), high-end, single-level cell (SLC) parts can easily reach more than $500 for a mere 32GB.

Currently, there are several differences between SLC- and MLC-based drives. SLC, which has been used for defense and industrial applications since the early days of solid-state drive technology, has an inherently better endurance (more read/write cycles) than MLC. SLC is also typically faster, especially when it comes to sequential write speeds (although read speeds are also lower for many low-end parts). On the other hand, MLC has higher density and significantly lower cost per gigabyte. 

But with the introduction of a new and powerful player to the SSD market, the rules of the game have begun to change. Intel (along with Micron) has released a series of solid-state drives, one of which — the Intel X25-M SSD — has been promoted by the company as the fastest SSD in the world. Athough there may be faster industrial-level SLC drives on the market, Intel’s is certainly one of the fastest MLC drives, boasting a whopping 250MBps read speed and 70MBps write speed.

Intel also claims to have improved the reliability of its MLC drives, to a level at which a user can write 100GB of data on the drive each day for five years. An average user can realistically expect a 10-year lifespan, but more demanding uses (servers, for instance) might strain the technology. For that reason, Intel has introduced a different SLC-based drive that’s more suitable for enterprise applications, the X25-E Extreme, which also offers 250MBps/170MBps read/write speed and at least twice the endurance.

Despite the revolutionary nature of Intel’s new MLC line, pricing remains the Achilles heel of the SSD market. An 80GB Intel X25-M costs just under $600 — about 30 times the price of a similar-size conventional hard drive. The new Intel X25-E Extreme, with only 32GB, costs more than $700 (due to its SLC technology), which has slowed its enterprise adoption rate.
 
However, Intel is far from the only player in the advanced SSD market. Samsung, which released the first consumer SSD in 2007, has also significantly improved its products in the past two years. In May 2008, Samsung announced plans to release an ultrafast MLC-based SSD that boasted an exceptionally large 256GB capacity. In November 2008, Samsung made good on its promise and announced that the new drives had entered mass production and would be on the market soon. The new drive will feature a read speed of 220MBps and an exceptional write speed of 200MBps. As with Intel’s SSD, price will be the determining factor. As of late November 2008, Samsung had not announced prices, but estimates are that the drives will command at least $1,000.

Other players in the ever-expanding SSD arena include Toshiba, which recently announced a 256GB MLC drive with about half the read/write performance of the upcoming Samsung model; and Sandisk, which announced a forthcoming SSD-related technology known as Extreme Flash File System (ExtremeFFS). According to the company (which was almost acquired by Samsung in 2008), this technology has the potential to greatly extend endurance and accelerate SSD random write speeds by as much as 100 times compared with existing systems. The ExtremeFFS can optimize a Vista OS to make much more efficient use of a Sandisk drive, and it can even learn user patterns in order to store more frequently used data in more accessible locations on the drive.

Some of the strongest players in the enterprise SSD market are relatively unknown to the general public. These companies include Memoright, Mtron, STEC, BiTMICRO Networks and Adtron, among others. Most specialize in manufacturing high-end SLC disks for industrial and enterprise applications. Mtron, for example, recently announced it will reveal a new SLC-based SSD in 2009 with unprecedented 260MBps read and 240MBps write speeds. However, given the company’s current-generation SSD pricing of about $900 for a 64GB drive, the new superfast drives will probably find few customers, even on the enterprise market.   

So what does the SSD market look like for 2009? Setting aside game-changing technologies such as Sandisk’s ExtremeFFS, the market will likely be divided into three segments. The first segment, traditional SSDs — high-end industrial/enterprise SLC-based drives with price tags of $1,000 or more — will gradually lose its appeal as more cost-effective high-end MLC drives reach the market. These new drives, which include Intel’s X25-M series (with a 160GB and even larger-capacity versions planned for 2009) and Samsung’s upcoming ultra-fast MLC drive (with a 512GB version planned for 2009), will present a more viable option probably in the second half of the year, given the predicted drop in flash prices.

Finally, in the entry-level consumer MLC-based SSD market, several companies (including OCZ, G.SKILL, Patriot and others) are now offering relatively cheap SSDs ($300 to $400 for 128GB drives) with better performance than most high-end conventional hard drives (above 150MBps read and close to 100MBps write speeds). The attractiveness of such drives should increase considerably when prices go below $200 for 128GB.