Do External Monitors Decrease Laptop Performance?

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Laptop performance can be measured in a number of ways, however it’s easiest for comparative purposes to speak about it in terms of raw processing power and graphic processing capabilities. 

When considering the relationship between laptop performance and external monitors, the impact upon graphics, as measured in frames per second (FPS), tends to be the best barometer.

If adding an external monitor to a setup for the purpose of having more than one display, the graphics processor in the laptop will require to work harder to generate both screens and so the performance of the laptop is likely to see a small decrease.

If however the resolution of both the laptop screen and external monitor are the same, and you configure the display settings to request that the laptop operates solely on the external monitor, there will be no decrease in performance.

Screen resolution and the relationship between the integrated and discrete graphics card will also have an impact on whether an external monitor will decrease (or in some cases even increase!) the performance of a laptop.

We’ll explore both in more detail below.

Whilst this article explores the impact of connecting your laptop to an external monitor. If you would like to learn how much extra power you can expect to see added to your electricity bill by connecting a second screen to your setup, you can check out our guide here.  

Does external monitor size impact laptop performance?

When the density of pixels increases on a monitor, the harder a laptop must work to fill each frame.

This means that at a higher resolution, say 4k, the maximum number of frames per second a laptop is capable of processing will be less than a lower resolution, for example 1080p.

So whilst the resolution of an external monitor will directly influence laptop performance, the physical dimensions of an external monitor will not. 

It’s generally accepted that a 1440p (QuadHD) resolution provides the best balance between performance and visuals for gaming as 1080p just doesn’t provide the crispest of detail whilst 4K makes it difficult for most GPUs to operate without experiencing some sort of lag. 

The table below shows how graphics card performance is impacted not by the size of the monitor but the resolution of a display.

VRAM, temperature of the machine, and the game being played are also factors that impact on graphic processing speed so the numbers in the table below are purely for representation purposes only.

Monitor Size Resolution No.of Pixels Frames per Second
24"
Full HD
1920 x 1080 = 2.07 megapixels
62
24"
Quad HD
2560 x 1440 = 3.68 megapixels
45
24"
4K UHD
3840 x 2160 = 8.29 megapixels
21
27"
Full HD
1920 x 1080 = 2.07 megapixels
62
27"
Quad HD
2560 x 1440 = 3.68 megapixels
45
27"
4K UHD
3840 x 2160 = 8.29 megapixels
21

The video below by the wolfgang YouTube channel also illustrates this impact of resolution on FPS in a side-by-side comparison. 

Can adding an external monitor increase a laptop’s performance?

Gaming and higher end laptops have dedicated GPUs to help render graphics (as opposed to asking the CPU to cater for intensive graphics requests as well as all of the regular operating tasks). 

Usually connecting an external monitor to a laptop’s DisplayPort or HDMI taps straight into this discrete graphics card and provides a boost to gaming performance vs playing on the laptop screen alone.

When Jarrod’s Tech tested the impact of playing on an external monitor across a number of games the outcome was between a 1% and a staggering 33% increase in FPS when displayed upon a 1080p monitor.

The average across all games tested at maximum settings was a 6.6% increase in frame rate when using an external monitor instead of the laptop’s own display.

Crucial Reminder!!! Just remember to achieve the same gains at home you’ll require to close the laptop lid, or if the lid needs to remain open for the machine to cool properly, request that only the external monitor display is active. Both of these actions will prevent the integrated Intel GPU from remaining active.

Does adding more than one external monitor decrease laptop performance?

This question is normally asked where a setup has one or more monitors set aside for general tasks with a dedicated display devoted to gaming. 

It’s easy to understand why we might expect gaming experience to be affected in this scenario as outside of gameplay the graphics unit must now render a huge number of additional pixels to populate the second and/or third screen.

TechTeamGB conducted a really useful comparison to test this theory and found that playing Cyberpunk 2077 on one monitor with a second monitor sitting idle on the desktop setting resulted in a meager loss of 1 frame per second during gameplay. 

Conducting a more graphic intensive task such as streaming on the second screen, and even streaming on the second and third screen combined resulted in a similarly small decrease in FPS. 

It should be noted that these results were recorded on a 2GB GTX 1050, with higher end graphics cards such as the RTX3080 showing no observable difference whatsoever.

If however your system doesn’t have a discrete graphics card the loss in FPS is likely to be far greater. 

So in conclusion, bearing in mind the factors of screen resolution, adding more than one external monitor to a machine that has adequate graphics processing capabilities will bring about almost no decrease in a laptop’s performance.

What are the downsides of connecting an external monitor to a laptop?

With a laptop that has a discrete graphics card it’s very possible you’ll experience absolutely zero downsides of connecting an external monitor. 

Extensive use of the additional display will increase power consumption slightly and it is possible that an increase in core temperature will be experienced should the display be of a high resolution. This will cause cooling fans to run more often at full speed thus creating more noise.

With a laptop that has an integrated graphics card only there will be limitations on FPS from the very beginning.

The addition of an external monitor in and of itself will not add a further negative influence unless a low end machine is being asked to render graphics for an external display that has extremely high resolution. 

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