What is a MUX Switch For Gaming Laptops? How Important is it?

June 2, 2022 Miguel Salas

“A MUX Switch creates a direction connection to the dedicated GPU increasing performance by about 15% as shown in lower left side in the image.”

That’s pretty much all you need to know. If you really want to understand how it does so, then keep on reading.

1. What is a MUX SWITCH?

To understand what a MUX Switch is, you must understand the problem with most gaming laptops:

As you probably know, there are two types of graphics cards installed on a laptop: the integrated (iGPU) and the dedicated (dGPU).

Because the dedicated GPU is several times more powerful it draws on more power (this means less battery life) , this is why it’s ONLY ACTIVATED when you game or when you launch an applications that requires it. (Usually super high graphics like gaming at 1080p or 1440p , not when watching videos)

However, due to the way most gaming laptops are designed, even IF the dedicated GPU is activated, the integrated GPU still plays a role, essentially BOTTLENECKING the dedicated GPU therefore reducing the overall graphical performance.

For gaming, this means less framerates.

How does the integrated GPU bottleneck the dGPU ?

Most laptops do not have a direct connection from the dGPU to the monitor, thus framerates must go through the integrated GPU.

High quality images produced by the dedicated GPU on most laptops (without a MUX Switch) , will have to go through the integrated GPU (blue) before they reach the monitor.

Because the iGPU is weaker it cannot keep up with the constant flow of framerates per second being output by the dedicated GPU thus it doesn’t fully deliver every framerate (or every pixel) to the monitor.

This decreases dedicated GPU performance (green) down to 10~15%.

MUX Switch to the Rescue

A MUX Switch eliminates the need for these framerates (output by the dedicated GPU) to go through the “integrated GPU” as shown below:

Both the dedicated GPU and the iGPU are connected to the MUX Switch which acts as a “gatekeeper” only letting data flow from one lane depending on the application. Gaming? dGPU get in, iGPU blocked. Youtube? iGPU in, dGPU blocked.

Thus a MUX Switch makes a direction connection between discrete graphics (dGPU) and the monitor.

This is why a laptop with a MUX Switch will have 10-15% more graphical performance than laptops without a MUX Switch.

A laptop without a MUX Switch CANNOT have a MUX Switch installed. It must come by default.

However…

You can still get that 10-15% fps increase without a MUX Switch by disabling optimus which is done by using an external monitor.

2. Optimus

What is Optimus?

Optimus is just a fancy word for the “display controller” or the system in charge of doing the automatic graphics card switch we described before. Ex: integrated GPU activated and dedicated GPU deactivated with basic tasks and the oppossite when gaming.

Optimus is represented by the green line below.

The moment you stop running high graphics apps like gaming. Optimus will only use the integrated GPU to process ALL images and route them to the monitor.

If you launch something like a game or any other app that requires way more high quality images per second, the discrete GPU(dGPU) is activated. However, the dedicated GPU data must still get routed through the integrated GPU (green line) to reach the monitor which decreases its performance.

A MUX Switch is meant to re-route the data from the dGPU directly to the monitor.

In order to do this OPTIMUS must be disabled and for this a RESTART is required. Without a MUX Switch, you CANNOT deactivate optimus because there’s just no other way for images to get to your monitor.

Gaming laptops with no Optimus:

There are a few rare gaming laptops that do not have Optimus thus they’re ALWAYS using the dedicated GPU even when you’re watching youtube.

This is good because it eliminates the need of a MUX Switch to increase performance but it’s also bad if you rely on battery power.

3. MUX Switch Alternative: External Monitor

The only way circumvent to disable optimus (without a MUX Switch) is by plugging in an external monitor to the HDMI port or display port as shown below. This is represented by the orange line in the preceeding figure.

If one of these ports is connected to the dedicated GPU, then you’re good to go. Just plug in an external monitor and get that extra performance when needed.

You can verify if any of these ports are connected to the dedicated GPU by going into the NVIDIA Control Panel in the task manager in the lower right corner:

Click on the Set PhysX configuration tab as shown below:

In my case, there’s no port connected to the 3050Ti RTX thus I’m screwed. No MUX Switch and not even an option to attach an external monitor!

Good thing you came across this article huh? Now you know you have to do some serious research before you buy a laptop.

4. Advanced Optimus

Advanced Optimus is a novel idea which is basically a system that acts like a MUX Switch (also bypasses the integrated GPU) with no need for a restart.

In layman terms, Advanced optimus does this, not by rerouting the dedicated GPU data directly to the laptop’s display but by rerouting it to a “virtual display”. Thus still avoiding to go through the integrated GPU.

This virtual display is simulatenously linked to the laptop’s display, in other words, what shows on the virtual (non-physical) display will instanteneously show up on the physical display.

The only problem with Advanced Optimus is that because there is no-restart involved, the iGPU is still running thus power and sort of bottlenecking the dGPU (this is signifncantly less than normal optimus though).

Summary

I apologize if the explanations are a little too complicated and entangled but it is extremely difficult to be accurate while at the same time breaking it down so that everyone understands.

With this in mind, there are four types of gaming laptops:

1. Gaming Laptops with Optimus:

Most laptops with dedicated GPUs have Optimus. This cuts down dedicated GPU performance by 15-20% but in return the battery will last a long longer when you run everyday basic applications. An external monitor through the HDMI port will disable Optimus and squeeze that extra dGPU power.

Note the stats bar shows the integrated GPU is still being used.

2. Gaming laptops without Optimus

Laptops with no Optimus do not use the integrated GPU thus the dedicated GPU fully takes oever in every single task. Battery life is severely reduced at the expense of maximum dGPU performance. It eliminates the need of a MUX Switch because the performance gain is pretty much the same. They’re very very rare. The Lenovo L340 is the only laptop I’ve come across with no Optimus.

Compare framerates with the first video.

3. Gaming laptops with MUX

Likewise you get maximum dedicated GPU performance with a MUX Switch. They will let you switch between the integrated and dedicated graphics at will thus giving you more control over power consumption . It requires a restart.

4. Gaming laptops with Advanced Optimus

It’s basically a laptop with a MUX Switch without the need to restart. Gaming performance gains is quite close to MUX Switch / No Optimus laptops.

FAQ:

Q: How to use a MUX Switch?

If your laptop has a MUX Switch, you can activate it by going through the “performance manager software” which is specific to a brand.

If your laptop is from Lenovo, this may be called “Lenovo Vantage”.

If your laptop is an ASUS it may be called “Armory Crate”.

It’s usually located in the lower right side of the screen next to all most commonly used options: sound, wifi, etc. as shown below.

Once you click on it, you should see an option labeled with the keywords “Hybrid Mode”. If that’s the case, then de-activate it. It will require a restart. After restart, select the option “dedicated GPU”. Or You could also see the option “MUX Switch / Hybrid Mode” as shown below. After a quick restart you will no longer have to choose an option, it will automatically be set up for you, it really depends on what kind of software you have.

Accesing the BIOS:

If your laptop has a MUX Switch but it does not have a “gaming panel center” or the option for a MUX Switch / Hybrid Mode isn’t there. You will have to do it manually. By this I mean, re-start the machine and access the Bios by pressing F2. You should be able to find an option similar to what was shown above.

If it doesn’t show up in a control panel center or the BIOS, then you probably need to do a BIOS Update.

Q: Is MUX Switch necessary?

MUX Switch are only necessary if you want to squeeze some extra GPU performance which means more framerates. The difference may or may not be worth it depending on the game. If you’re already hitting +120 fps with a 3060RTX laptop that doesn’t have a MUX Switch, then it’s probably not going to bump up your gaming or make any difference even for competitive gaming.

On the other hand, if you want to play at high or epic settings on a game like Call of Duty where you can barely get past 60fps with a 3050Ti, then yes a 3050Ti with a MUX Switch will make a huge difference.

A much more important factor to look at when buying a laptop is GPU TGP or Wattage. I’ve written a post entirely devoted to the issue, it’s actually a more determinant factor for gaming performance.

Q: Is there a MUX Switch Laptop list?

I have another post with a bi-weekly updated “MUX Switch Laptop List“. It’s definitely not the most complete list but it is a work in progress.

Q: How to check if laptop has MUX Swtich?

Three ways to do this:

A) Check your gaming center software:

This is located usually on the lower right corner. If you can’t find it, just type “Lenovo” or ‘ASUS’ in the search bar and an app with a similar name should pop up.

Once you open up this option, look if there’s any option with the keywords “hybrid mode” “MUX Switch”.

In my laptop as shown below there isn’t one:

B) Check the BIOS.

If you can’t find those options, then access the BIOS after a restart and look for those options.

Note: If you can’t find it on the BIOS settings, then do the a BIOS Update.

If you can’t find it after a BIOS Update, then your laptop doesn’t have a MUX Switch.

C) Do a quick google search

I would simply do a quick google search “Laptop Model + MUX Switch” instead of taking the time to go to the BIOS or doing an BIOS Update.

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Author Profile

Miguel Salas

I am physicist and electrical engineer. My knowledge in computer software and hardware stems for my years spent doing research in optics and photonics devices and running simulations through various programming languages. My goal was to work for the quantum computing research team at IBM but Im now working with Astrophysical Simulations through Python. Most of the science related posts are written by me, the rest have different authors but I edited the final versions to fit the site's format.