SSDs are getting better, still not there yet

To date, the solid-state disk has been a tech mirage. The vision is great, but it always seems to be just over the horizon.
Written by John Morris, Contributor

To date, the solid-state disk has been a tech mirage. The vision is great, but it always seems to be just over the horizon. SSDs have struggled to live up the performance promises, and they remain too expensive to provide any real competition to hard drives.

But that hasn't stopped companies from trying. A new generation of drives is getting us closer by improving the performance, and more important, using more advanced NAND flash memory to cut costs. In addition, Windows 7, which has now been released to manufacturing, includes features that should enhance the performance of SSDs.

Most reviewers agree that Intel's SSDs, the X25-M and X18-M, have come closest to delivering on the performance claims (not counting SSDs designed for servers from companies such as STEC and Fusio-io). This week, Intel announced its second-generation consumer SSDs, and several sites have already posted reviews with test results.

Like its predecessor, the X25-M G2 is a 2.5-inch drive available in 80- and 160GB capacities. Intel will release the 1.8-inch version, the Intel X18-M G2, later in the third quarter. The primary advantage of the new drive is that it uses the most advanced 34nm MLC NAND chips, rather than the 50nm MLC found in the first-generation drives. (MLC, or multi-level cell, NAND has two bits per cell, which doubles the storage density but also presents some performance and reliability challenges that require sophisticated controllers. Nearly all consumer SSDs use this type of NAND.) The 34nm process packs more bits on a chip, which translates to less-expensive SSDs. The old X25-M used twenty individual 8GB packages for 160GB total; the new X25-M G2 uses ten 16GB devices.

The new X25-M G2 80GB and 160GB will cost $225 and $440, respectively, in quantities of 1,000, and obviously a bit more at retail. Intel says that is 60 percent less than the original version at the same capacity, but this is a bit misleading since they are comparing prices at introduction. You can now pick up the original X25-M for $314 (80GB) or $599 (160GB). The new drives are still a long way from the industry's $1 per GB goal, never mind laptop hard drives, which are more like $0.37 per GB for 160GB (larger-capacity drives are even cheaper bit-for-bit). There were rumors that Intel would offer a 320GB version--which it could easily do by putting 10 NAND packages on each side of the circuit board as in the old design--but it didn't happen, most likely because the cost is simply too high. Still SSD prices have been coming down fast, thanks to a NAND industry that cuts manufacturing costs by roughly 40 percent each year.

The performance hasn't changed much, but it remains very good, according to the reviews. The sequential read performance was already at the limits of the SATA bus (300MB per second), so there's no real improvement there. And the sequential write continues to lag behind competitors, though PC Perspective notes that when Intel releases the planned firmware update for Windows 7, it should reach a consistent 80MB per second, still short of the fastest hard drives and SSDs. But the Intel drives shine on random reads and writes of small files. Compared with the first-generation drives Anandtech finds the new SSDs are 15% faster at random reads and 40% faster at random writes--and blow the doors off competing SSDs and, of course, hard drives.

Lexar Media also announced this week its second-generation SSDs. The 2.5-inch Crucial M225 series is available in capacities of 64-, 128- and 256GB for $170, $330 and $600, respectively. Lexar is claiming sequential read speeds of 250MB per second and write speeds of 200MB per second, but I haven't seen reviews of these models yet. Lexar is owned by Micron, which develops and manufactures NAND flash in a joint venture with Intel, but apparently these Crucial MLC drives aren't using 34nm chips since Intel claims to be the first.

Last week, Corsair introduced its Extreme series 2.5-inch performance SSDs at 32GB (X32), 64GB (X64) and 128GB (X128). These use Samsung's MLC NAND flash and an Indilinx Barefoot controller. Corsair claims these have the highest sequential read and write speeds currently available: 240MB per second and 170MB per second, respectively. The X128 is also sold as the Patriot Torqx, which Anandtech tested against Intel's new drive. He got a sequential read score of 256MB per second (almost exactly the same as the Intel X25-M G2) and an impressive sequential write speed of 140MB per second--nearly twice as fast as the 160GB X25-M G2. Corsair hasn't announced pricing for this series.

Though the NAND flash industry is hanging most of its hopes on SSDs, it continues to look for other applications to use up all those bits (aside from the iPhone 3G S). SanDisk mentioned on its quarterly call last night that it is now selling music on microSD cards for its slotRadio player at Radio Shack. And Disney Japan just announced plans to sell movies on Panasonic microSD cards bundled with regular DVDs, starting with Pirates of the Caribbean and National Treasure sometime in November.

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