No matter how fast the electronic interface got, drives were still limited by the speed at which the disk rotated. For consumer drives, that’s usually 5,400 or 7,200 revolutions per minute (RPM). Some high-end server drives spin as fast as 15,000 RPM, but they need to be installed in a well-cooled chassis. The average desktop or laptop just wouldn’t cut it, and they’re expensive anyway.
A different technology has been around for a couple years but is starting to come down into a competitive price range: solid state drives. Instead of spinning platters, there are flash memory chips inside of these drives.
Right now, a typical solid state drive, or SSD, costs a bit less than a dollar per gigabyte, while you can get a traditional spinning hard drive for about 10 cents per gigabyte. It’s not uncommon to find an SSD on sale for about 50 cents per gigabyte, though, and they definitely have their advantages.
Speed: Whoa, Nelly, are these things fast. For one thing, they don’t have to start spinning up when you turn on your computer — they’re just ready right away. They also don’t have to re-position the read head every time the computer needs a different file. That’s particularly important when the files it needs aren’t all right together on the disk, and they almost never are. Even a disk that’s been defragmented, or had pieces of individual files moved around so they’re stored together, can’t predict what files you might look for next, so there’s always some seek time involved.
So how much faster are they? Even the best consumer disk drives generally don’t crack 150 megabytes per second in real-world performance under good conditions. SSDs, on the other hand, can reach 500 megabytes per second. That makes a huge difference when you’re booting up or loading large multimedia files. Instead of sitting around for seconds that feel like hours, you can get right to work (or play).
Durability: Traditional disk drives are an anomaly in modern computers: They have moving parts. The processor doesn’t have those. Nor does the memory, or anything on the motherboard. There are fans, but no data moves through them. The only other component with moving parts is the optical drive for CDs and DVDs, and it’s not like we’re exchanging disk platters all the time. Get those mechanical parts out! Make it all electronical!
That’s exactly what SSDs do. Since they’re made of flash memory, there’s nothing moving around that can break, scrape or get stuck. Some laptops have special technology in their hard drives that detect when they’ve been dropped so that they can halt all movement inside; that at least minimizes the damage when the unit hits the floor. SSDs don’t need to do that, and take even less damage if they’re dropped.
Power: Again, no moving parts means less energy has to pulse through the drive. Even if you don’t care about conservation hippie stuff, using less power means your battery lasts longer on a charge. Gotta love that, right?
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