Buyer's Guide: Desktop PCs

With the deafening buzz created by mobile devices -- smartphones, tablet computers and laptops -- desktop PCs have lost some of their luster, but that doesn't mean the boxes will be fading from view any time soon. Where mobility isn't an issue and bang for the buck is, you can't beat a muscular desktop.

For $500, you can get a desktop to do most common business tasks -- email, Web browsing, word processing, spreadsheet manipulation, presentation creation and so forth. For $1,000 or more, you can get into more intensive computing tasks such as video editing or wrangling large databases.

Dell OptiPlex 580

A good place to start your search for a desktop is the operating system. What OS your new box has will be a major factor influencing other aspects of your purchase such as form factor and processor.

Most desktops sold today run Microsoft Windows. Now that the horrors of Vista are behind us, there's no reason to take heroic measures to circumvent the operating system that your next desktop will likely ship with, namely Windows 7. Win 7 comes in a variety of flavors, but you'll probably want the 64-bit Professional edition preinstalled -- 64-bit because it can take advantage of more memory than the 3GB ceiling of 32-bit Windows; the Pro version because it has more robust backup and networking features than Win 7 Home Premium.

An alternative to Windows is OS X, the operating system used by Apple's Mac line of computers. New Macs come with OS X 10.6, a.k.a. Snow Leopard. Two important changes made in the current version of OS X over its predecessor are support for Microsoft Exchange and full support of 64-bit processing.

Windows has the greater library of business software, including many companies' own in-house applications. But Mac hardware is more flexible than Windows gear -- with help from software such as Parallels Desktop 5, it can run Windows and OS X simultaneously.

Another alternative to Windows is Linux, which is offered in a number of distributions such as Red Hat Enterprise Linux, Novell SUSE Linux Enterprise Desktop, and Ubuntu. It takes some hunting to find desktops with Linux preloaded -- by custom order from HP, for instance, or from boutique vendors like System76 and ZaReason.

Shape and Size

You may not be able to judge a book by its cover, but you can tell a lot about a desktop by its enclosure or form factor.

If you're a forward-looking person, you'll most likely gravitate toward full tower desktops. They contain plenty of room for future expansion, typically including an array of PCI Express slots -- x1, x4 and, if 3D modeling is in your future, x16 for leading graphics cards -- and maybe an old PCI slot for legacy add-ons. They have multiple drive bays for hard and optical drives and are bristling with ports for plugging in peripherals. If a full tower is a bit more than you need, there are minitower units that will still give you a measure of expandability on a smaller scale.

Certainly the sexiest desktops to enter the market in recent times are the all-in-one models. Once the target of scorn by the computerati, Apple has managed to sprinkle some charm on the form factor with its iMac line, with Lenovo, HP, MSI, and others joining in on the PC side. Aside from their good looks, all-in-ones are especially attractive to the space-challenged. They take up a lot less room than a tower model by squeezing a PC into the back or base of an LCD monitor.

The problem with that kind of design is controlling heat, so the units can't use the more powerful -- and heat-generating -- CPUs and graphics cards found in tower boxes. However, all-in-ones arguably lead the way in other, more consumer-friendly technologies such as Blu-ray disc players and touch screens. Best of all, their price premium is coming down.

A third type is the small-form-factor PC, ranging from dictionary-sized desktops to tiny systems like the Mac Mini and ViewSonic PC Mini VOT132. These units certainly save space on the desktop; some can be mounted on the back of an LCD monitor to mimic an all-in-one system. But they have a high price-to-horsepower ratio and limited expansion capabilities -- accepting, for example, only half- rather than full-height graphics cards (which limit your choices severely) or no alternatives to integrated graphics at all. (More on graphics in a minute.)

Lenovo ThinkCentre M90z

Cores and Phenoms

After choosing your new desktop's body style, you'll want to decide on its brain, the central processing unit (CPU). As a rule of thumb, the faster your processor runs and the more cores it has, the more expensive your desktop will be. There's also a slight difference determined by chipmaker, with Intel systems costing more than comparable hardware with AMD CPUs.

Older Intel designs include the Core 2 Duo, Core 2 Quad, and Pentium dual-core processors, but the silicon giant's current lineup features (in ascending order of price and power) the Core i3, Core i5, and Core i7. The Core i3 and most Core i5 chips are dual-core CPUs that work (almost) like quad-cores, handling four processing threads simultaneously, thanks to what Intel calls Hyper-Threading Technology. The same scheme lets the quad-core Core i7 processors emulate eight cores. (Oddly, there are two quad-core Core i5 models that do not support Hyper-Threading.)

AMD, with no equivalent to Hyper-Threading, relies on four cores in its Phenom II X4 and six in the Phenom II X6. There are also dual- and triple-core Phenom II X2s and X3s, respectively. Below them, AMD courts bargain hunters with the Athlon II X2, X3, and X4 series of multi-core processors.

Unless you have intense computing needs such as video editing, a desktop with a quad- or six-core CPU may be overkill for you. In fact, most business applications can be handled with a good old dual-core processor -- particularly Intel's budget-priced Core i3 line, whose dual-cores act like virtual quads, or, to split the difference between dual and quad, AMD's Phenom II X3.

As a general rule, your budget will determine how much processing power you can buy, but the more CPU you buy now, the longer you'll be able to keep your desktop on your desktop.