We've already shown you some of the advanced ways to use multiple computers with one monitor, but what about the simple act of using multiple monitors with one computer? Read on as we go through the step-by-step basics of extending your computer's available visual real estate with another monitor.

Why multiple monitors?

If you've never used a computer with multiple monitors, more than one display might seem a bit overkill. That is, until you actually use it. Rather than try to efficiently manage all of your work in one space, multiple monitors allow computer users who use more than one application — basically everyone — to stretch out their work to another space, thereby reducing some of the inherent clutter in the modern multi-tasking workflow.

Hardware

Ok, so you get the reasons for doing it, but what hardware will be required to add another monitor? Laptop users won't need to add a thing. Typically, most laptops come with some sort of secondary video port, whether it be DisplayPort, HDMI, DVI, or VGA. These connections will allow you to physically make the connection to the display device.

Desktop users may or may not be so lucky. Look on the back of the computer, and you'll likely see one video port near where you plug in your USB devices (above). That's called the "onboard" video card spot. That video port typically isn't very good, in terms of handling 3D video and other graphics intensive work. Instead, onboard video does a basic job of displaying what's necessary to operate a computer, and little else. Look further down on your machine, toward where the PCI card slots are, and see if there is another spot for plugging in a monitor.

Typically, but not always, separate graphics cards will have at least two spots to plug in monitors. In the picture above, you'll notice two VGA ports and an S-Video port. These connections are legacy connections for connecting to a TV as well as connecting to two monitors.

 

Newer connectors that are all digital look like the ones pictured above. These connections, called DVI, are currently the most common display connector.

If your computer doesn't have an extra spot for connecting a monitor, what can you do? While it might seem a bit scary, the process is actually simple. Buy a new video card that's compatible with your machine. Most modern machines have PCI Express expansion slots. If your computer was sold after 2006, chances are it has PCI Express (pictured above). If you've got a computer that predates 2006, you'll need to check to find out whether you have the more modern PCI Express slots, or the older PCI slot (pictured below).

Some computers also have a slot for "AGP," which is short for Accelerated Graphics Port (pictured below). These slots will only work with video cards, making them ideal for video card expansion. As far as actual video cards, game players will need to do some additional research to find the best gaming graphics card. However, most every day users can simply buy the cheapest card with the connection needed (VGA or DVI) and be fine.

What if you don't have any of these connectors free, don't like opening up your machine, or want to add another monitor to a laptop? Fear not, expansion card challenged user, there are some other (albeit more expensive) solutions that'll save you from your dilemma. Matrox offers a solution called the DualHead2Go. The machine takes a VGA output and turns it into two monitor connections. For desktops, that means adding a second monitor. For laptops, that could mean adding a second and third monitor. Expect to spend $160 for the analog version (VGA monitor connection) and around $250 for the digital (DVI) version.

Once you've identified the style of expansion connector, all that's left to do is buy a video card or video box, connect it to the computer, connect a monitor, and start the machine. On a Mac, both monitors will show up and both should work properly. On a Windows machine, it's more of a crapshoot. We've seen some machines where the monitor will display both seamelessly, and others where users have to configure the machines. Don't fret; we'll show you exactly how to configure your machine, be it Mac or PC.

Software configuration

With Windows XP, the process is relatively simple. Right-click on the desktop, and select Properties. From there, head to the Settings tab, and you'll see multiple displays selected. Simply select the secondary monitor, signified by the number two, and check the checkbox that says "extend my Widnows desktop onto this monitor." You'll see the screen flicker a couple of times, and then a message will pop up asking if you'd like to keep the settings. Click yes, and you're set.

While you're there, you can also set up the orientation of the screens. If your secondary monitor is on the left instead of the right, simply drag the monitor from the right side to the left. Some video cards, like models from ATI and NVidia, offer more advanced options if you click the Advanced button, like the option to clone a desktop, or display all video played back at full screen resolution. Play around with those settings if you like, but most people will likely just stick to less advanced options.

Windows Vista, meanwhile, buries the control panel a bit deeper. Right-clicking the desktop gives you the option to customize the desktop, which sets wallpapers and screensavers, but doesn't give the extended options needed to add the second monitor. For that, you'll have to head to the Start menu, click on "Control Panel" and then find the "Appearance and Personalization" section. There, clck on Adjust screen resolution.

Now, a similar screen to the Windows XP screen will launch, and you can customize the location, screen resolution, primary monitor settings, or simply click "Extend the desktop onto this monitor" and activate a secondary monitor.

Meanwhile on the Mac side, it's pretty simple. Head to the system preferences menu, and click on Displays. You'll notice a resolution window appear on both monitors.

Mac OS figures, smartly, that if a monitor is connected to a port, then a user wants to see their desktop on the monitor. All a user needs to do is set the desired resolution.

You'll notice a tab called "arrangement." This tab lets the user arrange the monitors, but it'll also allow the user to do something Windows doesn't do by default: Mirror displays. See the checkbox in the corner? Now, the secondary display will mirror the primary display.

Now you should be good to go with all the information needed to extend your display. Got a question we didn't answer? Hit us up in the comments and we'll do our best to help.

[Image credit: Header image from Flickr user totalaldo. PCI / PCI Express: Clemmens PFIFFER, Vienna. Used via Creative Commons.]