Computers, Laptops & Tablets Accessories & Hardware Is Having More Than One Display Useful? Why an external monitor can boost productivity and performance by Mark Kyrnin Writer Mark Kyrnin is a former Lifewire writer and computer networking and internet expert who also specializes in computer hardware. our editorial process LinkedIn Mark Kyrnin Updated on July 08, 2020 The Ultimate Guide to Monitors The Ultimate Guide to Monitors Introduction Monitor Basics All About HD PC Monitors TVs vs. Monitors CRT vs. LCD Monitors Learn About Refresh Rates 3D Computer Displays CRT Monitor Resolution Specifications Why You Need a Second Monitor Add or Connect a Monitor Is Having More Than One Display Useful? Add a Second Monitor to Your Windows Laptop How to Connect Your Computer to Your TV You Can Use Your Old iMac as a Monitor How to Use Your iPad as a Second Monitor Calibrate It Yourself Why Monitor Calibration Is Essential Adjusting a Monitor's Settings Why Printer Colors Don't Match Monitor Colors Color Gamuts on LCD Monitors Troubleshooting Issues Testing a Monitor That Isn't Working Fix a Second Monitor Not Working Checking for Loose Power Cables How to Degauss a Traditional CRT Monitor Can Burn-In Happen to LCD Monitors? How to Change Refresh Rate in Windows Our Recommendations: Best Monitors The Best Computer Monitors The Best 4K Monitors The Best 27-Inch LCD Monitors The Best 24-Inch LCD Monitors The Best 32-Inch Monitors The Best USB-C Monitors The Best Monitors for Coding The Best Curved Monitors The Best 5K & 8K Computer Monitors The Best Touchscreen Monitors The Best Ultra-Wide Monitors Tweet Share Email Most laptops and desktop computers can run more than one display. A desktop display can be spanned across several external monitors, or it can be mirrored or "cloned" to appear on an external monitor. Having one or several monitors expands the workspace for a variety of tasks. If you have a small laptop, an external monitor can deliver improved image quality while simulating the externality of a desktop computer. Monitors can also be used in presentations, allowing an audience to view a larger display than the primary one can provide. In this guide, we look at why having more than one monitor can be advantageous. Higher Resolution at Lower Cost One reason for running multiple monitors is economic. While higher resolution displays have gotten significantly cheaper, it is still somewhat costly to get very high-resolution displays. For instance, many 4K PC Displays cost around $400 for essentially a 3200x1800 resolution. That is four times the resolution of a single 1600x900 resolution display. It used be cheaper to buy four small displays, each with 1920x1080 (HD) resolution, and tile them together for an image that is comparable to 4K. As 4K/UHD tech has gotten more affordable, that's no longer the case. Laurence Dutton / Getty Images What Is Needed to Run Multiple Monitors To run multiple monitors on a computer, you will need a graphics card that has more than one video connector. A typical desktop motherboard features two or three video connectors, while a dedicated graphics card may have more than four. Some specialized graphics cards have up to six video connectors on a single card. There are no software requirements to set this up, as Windows, macOS, and Linux all have the ability to run these graphics cards. The restriction usually comes down to the hardware. Many integrated graphics solutions are limited to two displays, while many of the dedicated cards can go up to three without too much of an issue. Be sure to read any documentation for the graphics card, as it may require that the monitors run on specific video connectors such as DisplayPort, HDMI, Thunderbolt, or DVI. As a result, you must also have displays with the required connectors. Spanning and Cloning When a second monitor is connected to a computer, the user is typically presented with two ways to configure the second screen. The first method is called spanning. This is where the computer's desktop will be displayed across both screens. As the mouse is moved off the edge of the screen, it will appear on the other screen. Spanned monitors are typically placed above, below, or next to one another. Spanning increases the overall workspace, which is helpful when running editing software, games, or applications that require a lot of multitasking. Displays can also be tiled across several displays. Here are some cases where spanning may prove useful: Multitasking: Host windows and applications on separate monitors, such as Word processing on one and web browser on the other.Editing software: Keep a zoomed-out preview image on one screen while zooming in and editing on the second. This is especially helpful on content creation-focused machines like MacBooks.Gaming: Expand the viewing space for games, or keep inventories and status windows within a dedicated monitor. Cloning means that a second screen is used to duplicate what is seen on the source display. The most common usage of cloning is for individuals who are giving presentations through applications like PowerPoint. It lets the presenter focus on the primary screen while the audience can watch what is happening on the second, presumably larger screen. Cloning is also useful when a laptop screen is too small for various creative tools or gaming rigs. Drawbacks to Multiple Screens While the economic cost of multiple screens is definitely a bonus over a single larger screen, there are drawbacks to using multiple monitors. Desk space is a concern, especially with larger LCD monitors. For instance, three 24-inch displays can take over an entire desk, compared to a single 30-inch LCD. Tiling displays may require specialized mounts to properly hold them in place and not wobble or fall over. This decreases the economic benefits compared to using a higher resolution display. Since the two screens are separated by the bezels that surround each screen, users may be distracted by the empty space that resides between the displays. This can make programs that span multiple screens a little awkward. Smaller bezel sizes help combat this effect, but there is still guaranteed to be at least some gap in the combined image. Because of this, most people have a primary and secondary screen. The primary sits directly in front, with the secondary either to the left or right. Finally, there are some applications that fail to use a secondary screen properly. The most common of these are among old DVD applications. They tend to display the DVD video in something called an overlay. This overlay function will only work on the primary screen. If the DVD window is moved over to the secondary monitor, the window will be blank. There are a few models that support dual monitor applications, but mostly they are in vehicles. This is less of an issue as DVD usage fades away in favor of streaming, but many PC games also only run on a single display. Should You Use Multiple Monitors? You may appreciate an external monitor if you do a lot of multitasking that requires windows to be visible at all times, or if you do a lot of editing work with graphics, video, or music software and require a dedicated preview window. Gamers that want a more immersive environment will also benefit, although the extra displays have some serious hardware requirements to produce a fluid image at higher resolutions. The average person may get by fine with a standard 1080p resolution display. There are also many more affordable high-resolution displays that make having two displays less economical.