How to Buy a Hard Drive

Your PC's internal hard drive is a real workhorse--the most critical component of your system after the CPU and memory. The hard drive is the hub where your operating system, programs, and data are permanently stored and accessed.

If you edit movies, take lots of digital photos, play games, or listen to music files on your PC, a big, fast internal Parallel or Serial ATA 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 400 or 800, 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 all of the PCs on your small or home network can share.

The Big Picture To enjoy multimedia on your PC, you need a spacious hard drive. Here's how to shop like a pro for an internal or external drive.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 we tell you which specs are the most important ones 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 buy 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 ofperpendicular magnetic recording, 1 terabyte (1TB) is the current maximum capacity for a single drive. As always, the drive you buy today will give you more storage capacity for less money than the one you could have bought a year ago.

This increased storage capacity has made it economical to turn your PC into a high-powered multimedia machine with plenty of room for accommodating all of your digital photos, a raft of digital music files, and the video files from your digital camcorder or from a TV tuner card. A single 1TB hard drive can store nearly 120 double-layered DVDs' worth of video.

When shopping for a hard drive, you must first decide whether to go internal or external. An internal drive is a bare drive that goes inside your PC, attaching directly to the motherboard or interface card via PATA or SATA (SATA is the newer standard supported by current PCs). 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. Another option is an external network-attached storage (NAS) device that connects to your router via ethernet.

Internal drives are suitable for replacing or expanding the storage of a single PC. You can either replace your system's primary C: drive or introduce additional drives to your system, depending on how many drive bays your PC has free (most PCs have at least one spare internal drive bay). Standard drives spin at 7200 rotations per minute and come with capacities of up to 1TB; high-performance models spin at 10,000 rpm and come with capacities of up to 150GB (15 percent of the storage a 1TB drive offers).

Internal drives commonly appear in two flavors: PATA (Parallel Advanced Technology Attachment), also commonly called IDE drives; and SATA (Serial Advanced Technology Attachment). All other things being equal--and prices generally are--you should opt for SATA, the newer of the two interfaces, if your PC supports that connection. SATA drives don't require you to configure jumpers as PATA drives do; their thinner cables restrict the flow of air inside your system less than PATA cables do, and they are easier to connect. SATA drives are sometimes slightly faster than PATA drives, but the performance tends to be nearly identical; you won't see a dramatic performance difference unless you combine drives in a RAID (Redundant Array of Independent Disks) setup. Still, you can be assured that the motherboard of any PC you purchase in the foreseeable future will support SATA drives, whereas they may not support PATA drives as time goes on.