Quantcast

What You Need to Know About Hybrid Storage Drives

By Wesley Fenlon

How hybrid hard drives uses SSDs as mega caches to shore up their read/write speeds without sacrificing storage space.

Apple rides at the forefront of a wave of technology companies moving away from physical platter storage towards faster solid state memory. The trend has spread from its mobile devices like the iPod nano and iPod touch to its laptops with the Macbook Air. Still, SSDs won't be cheap enough to replace inexpensive disk storage until they drop below $1 per gigabyte. While manufacturers wait for flash storage prices to become more affordable, they're looking at more affordable stopgap solutions in the form of hybrid drives.

Even Apple's interested in the idea: PatentlyApple uncovered an Apple patent for a hybrid hard drive with flash memory. With Apple, Intel and hard drive makers pursuing the technology, we may see hybrid drives break into the mainstream in 2012 ahead of a large-scale shift to solid state storage.

Here's what you need to know about hybrid drives before considering one for your next laptop.

Hybrid SSD/HDDs come in a few flavors. If you're up on your Apple hardware, you may be thinking "hey! Doesn't Apple already offer an upgrade option to SSD/HDD combos?" It does indeed--but not quite in the way we're talking about. The latest Mac Mini, for example, has a $750 upgrade option that includes a 750GB hard drive and a 256GB SSD. This option simply sticks two separate drives in your Mini. It's no different from having multiple hard drives in a computer tower. Except the SSD reads and writes more quickly, obviously.

A second distinguishing factor between Apple's current option and ideal hybrid setups: $750 is really, really expensive. With a 256GB SSD, you can easily run tons of applications and games off your OS drive. Hybrid drives seek to offer a more practical solution for those of us who can't drop that much cash on an SSD.

True hybrid drives use the speed of solid state memory more efficiently. They treat the SSD as a gigantic read/write cache for a moving platter drive, meaning data can be processed more quickly and frequently used applications should stay in memory. Intel's Smart Response Technology has the potential to be the most flexible implementation of this technology.

Everyone following PC hardware in 2011 knows about the Intel chipset fiasco that plagued Sandy Bridge earlier this year, but once Intel cleared up that mess motherboards fell out of the news cycle. That's fine--people interested in upgrading knew about P67/H67 motherboards and so on. But just a few months after Sandy Bridge debuted, Intel released a second round of chipsets for the platform to improve upon its overclocking options. Z68, launched in May 2011, also added a major new feature: Intel Smart Response Technology, which puts a HDD and SSD into RAID mode and uses the SSD as one big fat cache.

SRT offers flexibility by supporting SSD sizes up to 64GB. Intel recommends one of its own 20GB drives, but the takeaway is you can use a small SSD--say, a drive that would be too small to comfortably use as a boot drive--to bring your computer to near-solid state performance while still storing all of your data on a huge physical disk.

SRT has two cache modes: Enhanced and Maximized. The former performs writes to the hard drive and SSD simultaneously, which runs up against the limitations of how fast your HDD can write. Maximized mode writes data back to the HDD asynchronously. Cue delicious speed boost. Possible downside: if the SSD craps out, you're going to lose data.

There are some variables to keep in mind: a faster, larger SSD will obviously make a bigger difference than a smaller and/or slower one. If you use a variety of programs, the SSD won't be as efficient--it works best when it can cache regularly used data. But with an ideal setup, the results are impressive, cutting some load times by 40-50 percent.

For about $100 (and a Z68 motherboard) you could start taking advantage of Intel's SRT. Smart Response should make its way to a wider audience next year with Ivy Bridge motherboards. Everyone upgrading to Intel's 22nm processors will be able to set up a Smart Response SSD cache.

Apple's patented drive would likely work the same way, though the patent notes "Apple's Hybrid Drive will Hold an OS & Safari in Flash for Speedier Responses." Where would they put such a drive to work? Its "desktop" systems like the Mini and Mac Pro are obvious candidates. The 15-inch and 17-inch MacBook Pros could benefit from hybrid drives as well, but if the MacBook line is heading towards an Air-like redesign they may skip hybrids and go fully solid state.

Instead of waiting for Apple to release hybrid drives--assuming this patent actually makes it to the product state--look into some stuff that already exists right now. The OCZ RevoDrive Hybrid we reported on in June costs a kinda crazy $490 on Amazon in its 1TB/128GB SSD configuration. Seagate offers a more reasonable option with the $130 Momentus XT, which combines a 500GB HDD with a 4GB SSD cache. As usual, the best option is to buy the components separately and slap 'em together yourself.