Why you need a second monitor - and how to install one

One screen good, two screens better

You don't have to be a master coder, hardcore gamer or burned-out stock market trader to have a second monitor installed - it's a relatively cheap and easy upgrade that can be helpful in a bunch of ways, and both Windows and macOS are set up to take advantage.

You do need a certain kind of laptop or desktop setup to be able to install a second monitor, but it isn't complicated and we'll cover all of the basics you need to know here, as well as explaining why you might want to take the plunge with a second monitor.

The technicalities


Not all computers can run a second monitor right out of the box: if you're currently using a desktop or an all-in-one computer then you need a graphics card or chipset with two video outputs. Meanwhile, most laptops support an additional output besides the integrated screen, either through a dedicated port or through the use of a dongle adaptor.

All of which means your computer may or may not be able to support two monitors straight away but can almost certainly be upgraded to suit using some hardware trickery, either through a new graphics card or an additional dongle and cable. You're also going to need to buy yourself a second monitor that's compatible with the connection, of course.


It's important to bear in mind that powering two screens takes up more graphical processing grunt than powering one, so take that into consideration. Older desktops and laptops (including Chromebooks) can support two screens but you're not going to be able to get both of them running the latest video games at the maximum frame rates.

You can even set up a third or fourth screen if your main computer has the necessary ports to cope (or can be expanded to accommodate them), but the same caveat applies - you're going to need enough processing power to be able to keep all those displays running at once, otherwise the screens will be sluggish to update and may black out completely.

Installing a monitor


First and foremost you need to check your second screen is compatible with the outputs coming from your laptop or desktop. Most modern machines will use HDMI, DisplayPort, mini DisplayPort or USB-C, while older hardware typically uses DVI or VGA - check the specifications list if you're not sure and make sure you're buying hardware that matches.

For devices that aren't compatible, you may be able to find some kind of adapter plug to make everything work, depending on the connections. After that, if you can plug one end of a cable into a monitor and the other into a computer then you can set up a second monitor. It's not even necessary to switch off your machine first, although it usually helps.


On Windows, you can configure your screens by right-clicking on a blank part of the desktop and choosing Display settings (or just searching for "display settings" from the search box). You can change the orientation and resolution and choose which is the 'main' display (where the taskbar, Start menu and key dialog boxes all appear by default).

On macOS, open up the Displays entry from System Preferences and you can see all of the screens that are currently attached and detected - as with Windows, most of the options are self-explanatory. Use the Arrangement tab to set the location of your monitors and enable or disable mirrored displays (where the second display is a duplicate of the first).

Potential uses


As we've noted above, Windows and macOS don't need any special software or upgrades to make use of another screen once it's attached - they're both clever enough to adjust automatically - so you can carry on dragging and docking your application windows as normal. But what advantages does a second monitor give you over a single one?

You can keep two apps open side-by-side constantly for any purpose: watch a movie while typing out an essay, say, or take notes from a webpage without having to keep switching from your browser to a word processor, or keep applications like Spotify and TweetDeck in view permanently while you're working on something else on another of your screens.


Many of the more powerful desktop applications, such as office programs and video editors, have dual-screen modes to take advantage of an extra display. Take Photoshop, for example, where you can keep your images open on one screen and have all of your tools and dialog boxes available in the other, saving a lot of switching back and forth.

Having your file system open on one monitor while running another application on monitor two is another good example of how another display can boost your productivity. Okay, the same tasks can still be completed on a single screen, but you're spending less time and effort switching between windows and have everything available at a glance.