What it means: You've probably heard the term "hybrid drive" if you're thinking about buying a new computer. A hybrid drive pairs a traditional spinning-disk hard drive with a small amount of solid-state memory, the kind also found on solid-state drives (SSD) such as Flash drives. The combination gets you the large capacity of today's hard drives plus the speed of solid-state memory, and it costs less than an SSD.

Apple has a hybrid solution of its own for its iMac desktops, called the Fusion Drive. It also pairs a hard drive with solid-state memory, but there's a big difference: PCs' hybrid drives usually consist of no more than 32GB of solid-state memory, while the Fusion has 128GB of solid-state memory.

Why the buzz? The big advantage of a hybrid drive is speed. A hybrid drive helps your computer get up and running faster, because its solid-state memory caches your start-up files and frequently used programs, storing them temporarily so they can be used faster.

Hybrid drives, including the Fusion Drive, are supposed to work over time to make your computer even more efficient. They do that by learning which applications you use most and caching them. Apple says Fusion Drives also learn which photos, documents, and other files you open frequently, and caches those as well.

We tested a desktop, the Vizio CA27-A2, with a hybrid drive. We also tested the new iMac 27-inch desktop with a Fusion drive. Both were excellent performers.

To really understand the effect of these new drives on performance, you'd need to use your computer over time to allow the drives to learn your behavior and provide the best performance. Meanwhile, if you're ready to jump on these technologies now, a 1TB Fusion adds $250 to the cost of an iMac. Hybrid drives should add about $100 to a PC's price tag, but so far only a few manufacturers are offering them.