Over the last few years, gaming laptops have become so advanced that you no longer need a desktop PC for most workloads. Most gaming laptops come with all the newest features like variable refresh rate displays, desktop-class CPUs, and some even come with a mechanical keyboard. In this narrative of new features, however, the most talked about addition in recent years hasn’t been high refresh rate displays or ray-traced graphics but an ordinary add-on called the MUX switch. It is a feature that gives your gaming laptop the ability to bypass integrated graphics and use discrete graphics to deliver performance benefits almost instantaneously. Today, almost every laptop reviewer swears by it, calling the MUX switch a must-have feature in any gaming laptop. But how does a MUX switch work, and should you actually look for this feature in your next laptop purchase? That’s precisely what we are here to answer in this MUX switch explainer.
In this article, we will explore every facet of the fascinating feature that is the MUX switch — from its history to its inner workings. We will also answer a variety of questions that many PC enthusiasts might have, like how can you find out if your laptop has a MUX switch? And if it does, how to activate the MUX switch? The idea is to give you all the important facts about the MUX switch, so you know its benefits and limitations. If you are looking for specific answers, use the table of contents to move to the section that interests you.
What is a MUX Switch in Laptops?Brief History of Switchable GraphicsWhat Is NVIDIA Optimus Technology?Return of the Hardware MUX Switch
What is Nvidia Advanced Optimus?Nvidia Advanced Optimus vs Hardware MUX SwitchHow Do I Check If My Laptop Has a MUX Switch?
Check Manufacturer’s Companion AppCheck MUX Switch in BIOS SettingsSearch Official Support Page or Online ForumsHow to Turn on or off MUX Switch in Gaming Laptop?
Can You Install a Mux Switch After Buying a Laptop?What Are the Benefits of MUX Switch?What Are the Disadvantages of MUX Switch?What If My Laptop with a Dedicated GPU Doesn’t Have GPU Switch Option?Should You Buy a Laptop with a MUX Switch Right Now?
What is Nvidia Advanced Optimus?Nvidia Advanced Optimus vs Hardware MUX Switch
Check Manufacturer’s Companion AppCheck MUX Switch in BIOS SettingsSearch Official Support Page or Online Forums
Can You Install a Mux Switch After Buying a Laptop?
What is a MUX Switch in Laptops?
Before we look at the fascinating history of the MUX switch, we should first have a clear idea about what it is. Short for “Multiplexer“, the MUX is nothing but a toggle that allows users the choice to run their laptop display either through the iGPU (also called Optimus or hybrid mode) or through the discrete GPU. In current-gen gaming laptops, the MUX switch takes the form of a dedicated microchip that is placed between the iGPU and the dGPU.
Now for people who aren’t well versed with laptop nomenclature, iGPU and dGPU refer to the different graphics processors that are in your laptop. The iGPU is the graphics processor that’s usually located on the same die as the CPU. It is a weaker graphics chip used for basic tasks like video streaming, running the OS’ GUI, and other similar tasks. The dGPU (dedicated graphics processor), on the other hand, is a full-blown graphics chip (installed separately from the CPU) capable of carrying out high-performance tasks such as gaming or video rendering. They also have different power requirements, with the iGPU usually being a low-powered chip, while the dGPU is more power-hungry.
Brief History of Switchable Graphics
Now that we have taken a look at what the MUX switch is, we want to bring forth this feature’s interesting historical trajectory. It is a story akin to that of the Ouroboros. It’s been born and reborn again multiple times in the past few decades. The current conception of the MUX switch that manufacturers have been calling a “new feature” is, essentially, an old one.
The issue was that a typical laptop at the time had at least three separate display adapters – one for the LCD, one for the VGA port, and one for DVI/HDMI. This meant that if you wanted the ability to switch between integrated and discrete graphics, you would need multiple add-ons in the motherboard to route signals from and to the GPUs. This made the first-gen solution of adding hardware MUX cumbersome and expensive. This solution also required the user to restart their system every time they decided to switch graphics, as actual circuits needed to be changed.
Laptop manufacturers realized this shortcoming, and we saw second-gen switchable graphics come to the market over the next few years. This iteration involved more work on the software side, as the hardware switch transformed into software-controlled switches. So how did they work? Basically, what manufacturers did was they created something called a “Display Driver Interposer,” a kind of bridge that had information on both Integrated graphics drivers and dGPU drivers. That meant whenever you needed to switch between GPUs, there was no need to reboot the system, and you could switch between iGPU and dGPU in about 5 to 10 seconds by changing the display profile on the laptop.
Now, with the laptop industry moving towards switchable graphics, Nvidia released its own version of it in 2010 called “Optimus“. The implementation was highly advanced and virtually solved every single complaint that users had with the second-gen implementation.
As you can see in the diagram above, Optimus allowed the computer to decide which graphics solution it wanted to use for the particular task. For example, if it was running something light like Microsoft Word, it would switch to the iGPU and completely shut off the dGPU. And if it was running an intensive task like a game, it would drive the display through the dGPU.
This made Nvidia Optimus a solution with almost no drawback at the time. That means if a laptop manufacturer wanted to include a dedicated GPU in their systems, Nvidia’s solution was almost a necessity. And that is exactly what happened. Over the years, Optimus has become the dominant choice for manufacturers when it comes to switchable graphics, and to this day remains the most popular of choices, especially in budget gaming laptops. Today, almost every laptop with an Nvidia GPU ships with Optimus in some form or another.
Over time, we have come to realize that Nvidia Optimus was never perfect. The implementation has certain issues, which have come to the fore over the years. For one, Optimus essentially slaves the dGPU to the iGPU, which means it always uses the display controller of the iGPU. This causes the laptop’s display capability to be limited to that of the integrated GPU.
The current wave of MUX switches, which have been popularized by the likes of Alienware and Asus, are a reaction to this limitation. These hardware MUX switches are installed on the motherboard itself, so that these laptops can bypass the iGPU completely and have the signal go directly from the discrete GPU to the laptop’s display. And well, removing the bottleneck that is the iGPU in the process.
If you have been paying close attention to our explanation, you would have spotted a certain similarity that the new wave of MUX switches has with the older generation of switchable graphics. The current-gen MUX switches are a hardware add-on similar to the older switches and take the form of a dedicated microchip that resides between the iGPU and the dGPU. This can clearly be seen in Asus’ case, where they represent their MUX switch as an integrated circuit that connects to both dGPU and the display.
In a similar manner, keeping in mind the limitations of Optimus, Nvidia released a newer iteration of its technology in April 2020, and it’s called Advanced Optimus. The idea of Advanced Optimus was to solve the issue of both performance and features at the same time.
Nvidia argues that this solution not only solves the iGPU bottleneck in terms of performance but also makes other features like Variable refresh rate possible. Display signals in laptops without Advanced Optimus or a dedicated MUX switch go through the chip’s iGPU, and these GPUs typically lack support for G-Sync or other standards. Again, I emphasize most because some AMD CPUs, especially the higher-end ones do come with support for free sync.
Advanced Optimus has certain advantages over a normal MUX switch as it is automatic. That means it actively switches the graphical output depending on the use case instead of being toggled on or off manually. Like the older Optimus implementation, it gauges the workload and decides which GPU to use. Furthermore, laptops with Advanced Optimus also do not need rebooting to switch to dedicated graphics, as that work is now done by the “dynamic display switch” in the background.
Check Manufacturer’s Companion App
While MUX switches are an important advertising material for gaming laptops, most manufacturers don’t actually list them on their specs sheets. To check if your gaming laptop has a MUX switch, the first thing you should do is open the included companion suite like Armoury Crate on Asus machines, Alien Command center for Alienware, etc.
In our test laptop, which was an MSI GE67HX Raider, at the Beebom office, the MUX switch could be found under the features window in the MSI Center companion app. The MUX switch was labeled as ‘GPU switch’ and gave us the option of choosing either the “Hybrid” mode, which uses the iGPU as the primary display driver or the “Discrete Graphics Mode” to use the included RTX 3080 Ti as the primary driver.
Check MUX Switch in BIOS Settings
Some laptop manufacturers, though, don’t include the GPU switch toggle in their companion app but rather hide it in the BIOS settings of your system. This is mostly seen in Dell gaming laptops, as highlighted in the image below.
As for the reason why it’s in the BIOS and not the companion app, we are not sure. One reason could be that Dell is genuinely happy about their laptop’s performance in the iGPU mode and believe that the sacrifices that come with turning on the dGPU mode (lower battery, etc.) are not worth the trade-off. Some individuals have claimed this to be a ploy by Dell to force gamers to buy their Alienware series of laptops. But as we saw in our research, the MUX switch in Alienware laptops is also located in BIOS settings, so the claim doesn’t stand to scrutiny.
Finally, if you are unable to figure out whether your gaming laptop has a hardware MUX or not, you can simply look at the official support page for your device. Moreover, online forums like Overclockers.net and Reddit are also handy to find more information.
Now, one doesn’t really turn a gaming laptop’s MUX switch on or off because it doesn’t really act like an “on” or “off” switch. It’s better to imagine the MUX switch as a railroad switch, as all the MUX switch is doing really is guiding visual signals through specific paths, which can either be through the iGPU driver or the dGPU.
As we have already discussed, there is no single way to change the settings of your MUX switch, as each manufacturer has its own way of doing it. We have already covered the way in which you can find the GPU switch toggle on modern laptops in the section above. However, to expand on that, almost every companion app these days comes with a dedicated option like GPU Mode, GPU Switch, Hybrid Mode, or Graphics Switcher, which enables or disables the MUX switch/Optimus on your laptop. And if it does, you can always open the BIOS settings on Windows 11/10 laptops to change the setting.
As we have already mentioned, the MUX switch is a specific hardware chipset that is installed on the motherboard. It lies between iGPU (processor) and the graphics processor, which means that the MUX switch is not something that can be easily removed or installed at a later stage. This is reiterated by several manufacturers like Asus, who constantly remind us that MUX switches are soldered onto the motherboard and are not something that is user upgradeable.
There are a few tangible benefits when it comes to having a MUX switch. The most important advantage, the reason for which most users want a laptop with a MUX switch, is its performance. Now, the level of performance improvement will depend on individual systems and their configurations, but the fact that there is some performance improvement cannot be disputed. For that, we conducted a test to check the performance difference with the MUX switch on a gaming laptop enabled and disabled. So, let us find out if MUX switch can increase FPS in gaming or not.
For example, in our hands-on performance test, we found that switching to a discrete GPU using the MUX switch could provide anywhere from a 15% FPS improvement in some games like DOOM: ETERNAL to a paltry 5%improvement in other triple AAA games such as Control. We also tested a popular graphical stress test known as Furmark, and to our surprise, we did not specifically see any performance upticks.
Games/ApplicationAverage FPS with Hybrid modeAverage FPS with Discrete Graphics modeDoom: Eternal 162180God of War8590Control8890Furmark7575
Now, we have yet to come across such massive differences in performance on our laptop, but that might just be down to the specific settings used in the comparison. We tested all of our games at “Ultra” preset on a 1440p resolution, and it seems that the iGPU turns out to be more of a bottleneck when pushing ultra-high framerate in older games when you look at other performance comparisons. So if you are someone who plays a lot of CS:GO, you might feel a huge difference in performance when in the “Discrete” graphics mode.
Furthermore, using the laptop in dGPU mode can unlock certain features that were not available in the iGPU mode, like the ability to use Nvidia Shadowplay more often. In our MSI laptop, when in the hybrid mode, we were unable to record the screen when not inside a video game. But when turned on the dGPU mode, we were able to do so. This is because “Shadowplay” (used to record video games) uses the H.264 decodes in Nvidia’s dGPU that require a direct connection to the GPU.
The MUX switch, while it comes with a variety of benefits, is a double-edged sword at the end of the day. The one aspect of gaming laptops that’s generally the most affected by dGPU mode is battery life. This makes sense as Optimus or the modern standard of switchable graphics were a result of the movement towards achieving battery life on performance laptops. The iGPU only mode consumes less power than the dGPU mode as the graphics processor in Optimus/ Hybrid mode is only turned on when required. In the dGPU mode, however, the graphics card is constantly running in the background, which means that the overall power consumption will always be higher.
This was evident in the battery test that we undertook on our MSI GE67HX laptop. The test was rather simple and entailed running a 4K YouTube video for 20 mins on 50% brightness. We believe that the concept of comparing battery life during gaming does not make a lot of sense, because most gamers don’t use their gaming laptop on battery – as it’s heavily neutered in this mode.
A popular question that many users might have is – whether they can do anything to improve performance on their laptop if they don’t have a MUX switch. The answer is yes. There are other ways in which you can bypass the iGPU to improve your performance. The easiest way to bypass the iGPU is to connect an external monitor to your laptop by running it through the display port or the HDMI port.
But before you do this, make sure that the port you are running your external display through is powered by your dGPU. If you don’t know specifically which output your GPU powers, follow the steps below to find out:
Once you have opened the app, expand the “3D Settings” option in the left sidebar. Then, click on “Configure Surround, PhysX“.
In the configure window, you will see where your laptop display is connected and whether it’s powered by the iGPU or dGPU on the bottom left. As you can see in our case, the display is being powered by the discrete GPU – RTX 3080 Ti.
Note: For this to work perfectly, you need to make sure that your laptop’s screen is not being mirrored and instead running just on the second-screen-only mode. If you keep your laptop screen on, it will automatically switch to the iGPU driver.
Should You Buy a Laptop with a MUX Switch Right Now?
Now, coming to another important question – whether you should buy a laptop with a MUX switch or not? Well, the answer is complicated.
