How to Buy a Hard Drive

Where the rubber meets the road, your PC's internal hard drive is the real workhorse--the most critical component of your system after the CPU and memory. It's where your operating system, programs, and data are permanently stored and accessed.

If you edit movies, play games, or listen to music files on your PC, a bigger, faster, and more reliable internal hard drive can dramatically improve your overall computing experience. If you need more storage or a means to back up your PC's internal drives, you can add an external hard drive--available in USB 2.0, FireWire, or external SATA flavors. And if you want centralized storage, consider buying a network attached storage device. NAS devices are continually improving, and can be a convenient way to add storage that can be shared between all the PCs on your small or home network.

The Big Picture To enjoy multimedia on your PC, you need a spacious hard drive. Here's how to shop for an internal or external drive like a pro. more

Key Features Don't know capacity from rotational speed or IDE from SATA? We define the terms you're likely to see when shopping for a hard drive, and tell you which are the most important specs to consider. more

Hard Drive Shopping Tips If you outgrow your existing storage, it can be easier and cheaper to upgrade a drive than to get an entirely new PC. When you're ready to start looking, print out these tips for handy reference. more

The Big Picture

Today's hard drives have stunning capacities: With the advent of perpendicular magnetic recording, 750GB is the current maximum capacity for a single drive. And as always, the drive you buy today will give you more gigabytes for less money than the one you could have bought a year ago.

This increased storage capacity has made it possible and even economical to turn your PC into a high-powered multimedia machine with plenty of room to store all your digital photos, a raft of digital music files, and even those vast video files from your digital camcorder or from a TV tuner card. A single 750GB hard drive can store nearly 100 double-layered DVDs' worth of video.

When shopping for a hard drive, your first decision is whether to go internal or external. By internal drive, we mean a bare drive that goes inside your PC, attaching directly to the motherboard or interface card. An external, direct-attached drive uses the same basic mechanism, but it's housed in an enclosure that connects to your PC via the USB 2.0, FireWire, or eSATA bus. Also available are external NAS devices that connect via ethernet, typically to your router.

On one hand, internal drives are suitable for replacing or expanding the storage of a single PC. Since they reside inside your PC, they provide a convenient out-of-sight, out-of-mind experience. Detachable external drives, on the other hand, are more versatile. These drives let you add storage capacity to a PC with internal drive bays or connections that are maxed out. They can be shared amongst multiple PCs and stored in a safe place when used as backup media.

NAS devices allow easy access from any PC attached to your network and can be placed in a relatively safe location. They also tend to offer perks like printer and Internet file access so you can easily share printers across the network or access files from anywhere on the Web. NAS's biggest drawback is that you need to transfer data via ethernet, typically using the TCP/IP protocol; this generally makes NAS your slowest option.