How to Buy a Hard Drive

Hard-Drive Shopping Tips

Are you ready to take the plunge and buy a big new hard drive for your PC? Here are PC World's recommendations for what you should consider, both before you buy the drive and when you're actually shopping.

Determine whether your PC can take advantage of a new drive. Newer PCs can make best use of a new drive's increased performance and capacity. An old PC with a slow CPU and limited RAM won't be able to fully exploit the performance potential of a new drive. You've probably reached the point of diminishing returns if your PC's interface speed--say, ATA-33--is slower than the interface speed of the cheapest drive available.

If your middle-aged computer is still working acceptably, more storage capacity and speed may be just what the doctor ordered. Installing a new drive as your main drive for running Microsoft Windows and various productivity applications might improve performance appreciably. Older PCs may need both a PCI interface card to get the best drive performance and a vendor-supplied driver or BIOS update to be able to recognize the capacity of large drives; Windows XP's drivers allow use of a drive's full capacity as well.

Make sure your case has space. Most desktop PC cases have at least one, and sometimes several, internal drive bays--places where you can mount extra hard drives. But check your manual or open the case: If you have a smaller, low-profile case, you may not have room for another internal drive, meaning that you may not be able to use the old and new drives simultaneously.

Also, check your power supply to see whether it has a spare plug for an additional internal drive. Another consideration: Will the power supply have enough juice to run an extra drive along with your system's existing components?

Supersize your purchase. It's smart to buy a drive with more capacity than you think you'll need. If you're absolutely sure that you won't be using multimedia-intensive applications that eat up huge amounts of space (such as programs that edit video), or storing digital photos or MP3 audio files, you might not need a maximum-capacity drive. But be sure to anticipate your future needs when deciding on the size of your new drive--especially if you plan to keep your existing PC for a couple more years.

Match the drive and interface speed. The ATA-100 and ATA-133 interfaces of current drives are faster than the internal interfaces on many older PCs; check your PC manual or contact your computer vendor to find out for sure. An easy-to-install interface card (about $25) can guarantee that you get maximum performance from your new drive. If you want to add a SATA-300 drive to a system with SATA-150 connectors, however, just do it. The nominally slower interface should not choke the performance of a SATA-300 drive.

Use an external drive for backup. External drives are great for backing up your PC, and many models have one-touch backup buttons that make the process even easier. The fastest external hard drives are the new eSATA models. Make sure that you have at least one free internal SATA port for models that come with a pass-through cable, or buy a model that that offers eSATA ports through a PCI interface.

Use a portable drive with your notebook. External models that use hard drives intended for laptops tend to be optimized for mobile use. One relevant feature is a ruggedized enclosure with a high shock rating, meaning that it can absorb a typical impact from a desk to the floor, for example. Some drives may also have g-force sensors that can detect when a drive is in motion and park the heads to avoid damage to the disk. Typically, though, that feature is found on internal notebook drives, rather than on add-on drives.

Consider a NAS device. They're a great choice for backup as well as for making photos, videos, music, and other files available to everyone on your network. NAS devices connect to your network via ethernet, which means middling performance, but in most cases they also include USB 2.0 ports to share a printer or to expand storage capacity in case you run short in the future. See our Top 5 Networked-Attached Storage Devices for pricing and specs.

Look for bargains. Competition among hard-drive makers is intense, and dealers often run specials that let you pick up a new drive for an amazingly low price. These deals tend to be on smaller-capacity or slower drives, however. Don't expect specials on the largest-capacity drives, since these may be in short supply and usually sell at close to list price until the next generation of drives appears.

Buy a retail kit. Hard-drive kits include mounting hardware, cables, detailed instructions, and (often) software that eases installation. A kit may also include an application for cloning the contents of your old hard drive onto the new one, which then becomes your new main drive. If you buy via mail order, be sure to get the kit. The alternative is a "bare drive," essentially just a drive in a Mylar bag, often without screws, software, or even instructions beyond a technical data sheet. Bare drives are sometimes available online at bargain prices, however, and plenty of online installation help is available.

Use add-on software. Power users who purchase a bare drive and aren't running Windows XP may need extra software to ease the process of integrating the new hard drive into their PC. Even if you buy a packaged drive upgrade kit, you might want to use Symantec's Ghost or Acronis's True Image to back up and clone a drive. Symantec's Partition Magic and Acronis's Disk Director let you fine-tune how your new drive stores data.

Final Recommendations

General users: If you typically use your PC for Web surfing, working on Microsoft Word documents, handling e-mail, and perfiorming casual digital imaging, a lower-capacity drive may work for you. Opt for an inexpensive 300GB drive, using whichever interface is convenient for your needs.

Multimedia hounds: If you store a lot of digital images, audio, or video, consider buying a single 750GB or 1TB drive. If you also edit images and video, go for internal or external models on our Top 5 hard-drive charts that show the best test results on related imaging tasks; an eSATA drive will give you the best performance.

Gamers: A popular choice for performance-hungry gamers is a RAID 0 rig with two Western Digital 10,000-rpm WD Raptor drives. This kicks up your performance but limits capacity, since the WD Raptor is available only in 36GB, 74GB, and 150GB sizes.

Shared storage: If you want a NAS device, get one with the largest capacity you can find--gigabytes go fast when several people are backing up their own digital photo and MP3 collections. Also, aim for one that's easy to upgrade, in case you need to swap out a drive down the road.