Though they require a lot of room under or on top of your desk, full-sized desktops are the least expensive and the easiest to upgrade and repair. They also offer the most features and options.

At less than half the size of full-sized desktops, compacts or slim desktops are ideal if you lack space under your desk or you plan to put the computer on the desk itself. Like their larger brethren, compact desktops tend to be inexpensive. But they may be more difficult to upgrade and repair.

These computers incorporate the computer and monitor in one case. The components are tightly packed behind and underneath the display, making them difficult to upgrade or repair. Meant to be space-savers, they’re also designed to look less stodgy than traditional computers. You’ll pay a premium for these models.

The sky’s the limit for gaming systems. You get the fastest processors, the most sophisticated graphics cards, multiple large hard drives, and lots of RAM. Cases are usually large and offer room for additional RAM and other improvements.

A 10- to 13-inch laptop is best for people frequently on the move.

Why? For one, these laptops are typically light enough to be brought, say, to and from your office without needing the strength of a powerlifter. They may not have the absolute fastest processors around, but laptops in this size range are nowadays more than capable of handling everyday productivity tasks with ease. Battery life varies but should get you through a typical workday with no questions asked.

This size range offers the ideal balance of performance, portability, and price for many users. Midsized models are a good choice if you take your machine along less frequently or if you need to use it extensively for work or school. Such a laptop can easily be configured as a desktop replacement.

Until a few years ago, only 17-inch and larger models had graphics processors with dedicated video memory, but now some 14- to 16-inch models have them, making them suitable for gaming.

For photo editing, our tests of the 15-inch MacBook Pro with Retina display, $1,800, reveal its screen to be among the best we’ve seen for color accuracy and crispness.

For folks wanting a desktop replacement, big enough to sit semipermanently in one place but portable enough to take from room to room, these laptops will deliver. They tend to use top-performing processors with standard hard drives that give you tons of storage, though not top performance.

You might find some with better speakers than smaller laptops can offer. However, they still won’t sound as good as external speakers. And, of course, the larger screen can make it more comfortable to work on multiple windows or large spreadsheets.

Chromebooks are based on Google’s Chrome operating system. They’re generally inexpensive, with some starting at $170. They’re designed for users willing to work on and store most of their files online. Chromebooks are quick to start up, partly because the operating system doesn’t place the demands on the computer that a heavy-duty OS such as Windows does, and partly because they use solid-state drives instead of hard drives.

On the downside, there’s not a lot of storage space on a Chromebook. You need access to the internet to get the best work out of one of these machines. And these aren’t workhorse computers, though they are fine for creating and sharing documents, web surfing, email, streaming videos, and light gaming.

The tabletlike features in Windows 10 make convertible laptops an appealing category for serious work and casual play.

These look like a regular laptop, but the display either pulls out of the keyboard or twists around and lays flat so that it can be used like a tablet. What distinguishes detachables from tablets are the keyboard docks that come with them.

See our tablet buying guide for detailed information about shopping for a tablet. But in brief, for some users a tablet can take the place of a laptop. These machines are lightweight and highly portable. They’re multifunctional, serving as web browser, e-book reader, movie viewer, and music player.

They weigh from just less than a pound to about 1.5 pounds and have 7- to 10-inch touch screens. And in our tests, battery life ranged from 4 hours to nearly 13 hours. Tablets are not ideal for office productivity tasks, but you can add a keyboard to many of them.

Speed matters. Processors with multiple cores can process more data simultaneously. You can check Intel or AMD's website to see how many cores a processor model has.

Clock speed, measured in gigahertz (GHz), along with the number of cores and other factors, determines how quickly a CPU can process information. Many processors can up the speed a bit for a brief time to yield maximum performance. Generally, within a processor family, the higher the clock speed, the faster the processor. Clock speeds typically start at around 1 GHz for a mobile processor. Speeds can exceed 4 GHz for a desktop processor.

Power Consumption
Another important factor when choosing a processor, especially for laptops: Lower power consumption equals longer battery life.

If you’re looking for a very basic or budget computer to web surf, email, and work on Office documents, the Intel Celeron, Pentium, AMD A4, or A6 will suffice. If you plan to do some simple gaming as well, the Intel Core i3, AMD A6, or A8 should do the job.

If you plan to watch videos or play mainstream games, the Intel Core i5 and AMD A8, A9, or A10 are good choices. And if you’re a gamer or plan to edit high-definition video, go for a high-end processor such as the Intel Core i7 or AMD’s Ryzen line.

How Much Memory?
The more memory a computer has, the faster it is, up to a point. Memory is measured in gigabytes (GB). On desktops, 8GB is common, and many laptops include 8GB of RAM. For anything other than heavy multitasking or video editing, 4GB is plenty.

Operating System
Windows 10 brings a more uniform interface across a variety of devices: computers, tablets, Xbox consoles, and smartphones. In addition, “universal apps” developed for Windows 10 will look and work the same on a variety of devices. And far more games are available for Windows computers than for Macs.

Macs can be more expensive, but they’re less prone to most viruses and spyware, and Apple’s support has been tops in our surveys. The company’s phone support is free for only 90 days, but you can get unlimited technical support through the Genius Bar at any Apple Store. The latest version of macOS (previously known as OS X) is called High Sierra and was released in fall 2017.

Graphics Adapter and Graphics Memory
Also known as the video card, graphics processing unit (GPU), or graphics card, this hardware is responsible for drawing what you see on your screen. Graphics processing comes in two basic flavors: It can either be integrated into the same chip that’s running the rest of the computer or it can run on a discrete piece of equipment.

Most computers have integrated graphics. This has usually been the less expensive and lower-performing option—fine for most tasks but not for serious gaming. If you play mainstream and extreme games with all the visual effects turned on or if you edit video, especially HD and Ultra High Definition (4K), you need discrete graphics. Light video editing and gaming and all other typical computer tasks will do fine with integrated graphics.

Some new CPUs integrate discrete-class graphics, offering excellent graphics abilities without adding a separate chip.

Integrated graphics use up part of your system’s memory, so make sure you have at least 4GB. If you choose a system with discrete graphics, look for at least 2GB of graphics memory. Gamers should get 4GB or more.

Solid-State Drives: SSDs are a different type of storage technology, letting your computer access data without the moving parts required by a traditional hard drive. They are also the single largest performance boost you can give a computer over an identical computer with a hard drive.

SSDs don't have the spinning disk of a conventional hard drive, so they use less power, work more quietly, and should be more resistant to damage—and less likely to fail mechanically.  And because there are no moving parts, access to data should be quicker.

Although they once cost several times as much as traditional hard drives and had smaller capacities, prices are coming down and capacities are inching upward. In general, Consumer Reports recommends solid-state drives over hard drives.

Hard Drives

Also known as a hard disk, this type of drive uses a spinning hard disk and uses more power than a solid-state drive. It is also slower overall.

Bigger is better. Hard-drive sizes are measured in gigabytes and terabytes, and commonly range from 250GB to more than 1TB.

Speed is equally important and is measured in rpm (revolutions per minute). A slow hard drive will take longer to start up the OS and programs, and complete tasks (such as installing programs or scanning your hard drive for viruses).

For best performance, get a desktop with at least a 7,200-rpm hard drive or a laptop with a 5,400-rpm hard drive.

Hybrid Drives
Lower-priced hybrid drives, which combine a hard drive with solid-state memory, represent a good compromise.

Optical Drives
Blu-ray Disc (BD) drives are the newest standard. They’re capable of playing Blu-ray movies and can store 25GB (single layer) or 50GB (dual layer) of data.

Many of today’s laptops come without an optical drive, saving weight and cost. With high-capacity flash drives available, extra storage isn’t a problem on these models. But installing older software—usually distributed on a CD or DVD—could be a problem. Most of today’s software is distributed via download, so there’s little need for an optical drive.

The Battery
When not plugged into a wall outlet, laptops use a rechargeable lithium-ion battery for power. Laptops go into sleep mode when used intermittently, extending the time between charges.

You can lengthen battery life if you dim the display, turn off WiFi connectivity when it’s not needed, and use only basic applications.

Some laptops, most notably Apples, Ultrabooks, and other thin-and-light models, have nonremovable batteries, which may be costly to replace when run time starts decreasing.