You’ve probably glossed over the boring headline and aren’t even reading this, but it’s a lot more important than it sounds for the computer industry and computer users.
This is the tipping point for SSDs to become mainstream.
Currently, good SSDs (the bad, cheaper ones generally aren’t worth buying) are small and expensive. Intel’s excellent X25-M series, the gold standard, is about $450 for 160 GB.
SSDs based on this 25nm flash are likely to offer 160 GB in the $200 range and 320 GB in the $500 range.
It’s hard to overstate the performance gains that SSDs offer. It’s not the sort of incremental, you’ll-notice-it-5%-of-the-time gains that new CPUs usually offer.
If your computer feels slow, it’s almost definitely the hard drive’s fault.
If you’re waiting a little longer than usual for a popular website to render its Dashboard or show you an encyclopedia page or tell you which of your old high-school friends have gotten fat, you’re probably waiting for some hard drives in a server somewhere.
Nearly every slowdown of modern computer usage is caused by a very fast computer that’s sitting around doing nothing while it waits for its hard drive to move its heads.
Seek time is the delay required for the drive’s heads to move to the requested location on the disk, stabilize, and start reading or writing the data. Most hard-drive delays are seeks, not big sequential transfers1.
Ten years ago, the best consumer-class hard drives had seek times in the 12ms range. Today, most good drives are in the 8ms range. Got that? In a decade, we’ve made huge gains in nearly every other aspect of computer performance, and hard drives are much faster than they used to be. But seek time is still very high, and is still the bottleneck for everyday computer performance.2
SSDs — these tiny, laptop-hard-drive-sized boxes that have no moving parts and emit no noise and cost only $450 for 160 GB today — have an effective seek time of 0ms.
Seeks become effectively free. (Technically, they do take some time. But it’s well under 1ms and close enough to zero, relative to hard drives, for the sake of argument.)
Imagine if nearly every computer slowdown vanished. That’s what it’s like using a good SSD.
And it’s very likely that, in 2010, SSDs will finally reach mainstream-friendly prices and capacities.
I’m incredibly excited about this. Say what you will about my geekiness or overenthusiasm if you’ve actually made it all the way through this post, but the first time you use a computer with an X25-M, you’ll be this excited, too.
Average people don’t realize how little of a hard drive’s performance is bottlenecked by the maximum transfer rate, which is why new interfaces always advertise their sequential-transfer rates. USB with 60 MB/s vs. Firewire 800 at 100 MB/s vs. SATA at 150+ MB/s. It doesn’t really matter — when you’re waiting for seeks, which is most of the time, you’re lucky if the drive transfers more than 10 MB/s. There’s a great car analogy here with the everyday relevance of top speeds if you want to make it. ↩︎
What makes ridiculously expensive, 15,000 RPM server-class hard drives worth their cost to server admins is the reduction in seek times down to the 5ms range. They’re worth a huge price premium just for that. ↩︎