New laptops are implementing MUX for greater performance by disabling the iGPU and using only dGPU. Its little complex to understand. We tried to divide the technology understanding in below topics to make this little easy to understand.
What is a MUX Switch for gaming laptops?
A MUX Switch lets you disable the integrated graphics in your gaming laptop, giving you a performance increase in games at the expense of bad battery life.
To understand what a MUX Switch does, first we have to understand how Nvidia optimus works.
What is Optimus?
Most gaming laptops have two GPUs, The integrated graphics(iGPU) which is part of the processor, So Intel or AMD can be anyone, and the discrete graphics (dGPU), Example : Nvidia RTX 3060 , AMD 6800M etc.
The dGPU is more powerful, So it burns more power. Laptops are devices where battery life is very important. So Instead of using the heavy powerful graphics all the time, Laptops are designed to use lower power integrated graphics (iGPU) instead. The Dedicated GPU (dGPU) is still there and ready to be called when needed.
So When you open a game or some other GPU intensive workload, the system is smart enough to run the workload on the more powerful dGPU. This is how Optimus works, also known as MSHybrid.
But Optimus is having a Bottleneck. When running a game, the frames required by the games are generated on the dGPU, but they’re first send through the iGPU to the screen. This means that in many scenarios the iGPU acts as a literal bottleneck, and iGPU is not that powerful to handle dGPU frames at the same speed. and this is why it bottlenecks the game performance. and this is why being able to disable Optimus results in a performance improvement in games.
So basically on average Optimus off gave a 17% FPS boost in some titles. This is at maximum setting levels too, lower settings levels generally see an even higher boost.
What is a MUX switch?
A MUX Switch or a multiplexer is a switch which manually enable or disable the integrated graphics. It does this by physically changing the connection between the GPU and the screen. Being able to disable Optimus therefore requires that the laptop has physical hardware support for this feature, this is not something you can upgrade yourself. You cannot simply disable the integrated graphics through device manager in Windows, this does not change how the GPU and screen are physically wired.
We have to restart after enabling or disabling Optimus through Windows software to apply the change. This is a bit of an inconvenience if you’re changing frequently, but if you’re always gaming on wall power anyway then it makes sense to leave Optimus disabled.
With Optimus disabled, the integrated graphics are no longer available. We can't see them in task manager anymore, instead only the discrete graphics are available. This is like a regular desktop PC now, where the screen is connected straight to the high powered GPU. Gaming performance should now be improved, but if you need to run on battery power the run time will be less.
What is NVIDIA Advanced Optimus ?
So Nvidia Advanced Optimus is similar to this but when you switch the optimus for dGPU connection you need not have to restart in case of Advanced optimus.
Hope this clarifies your doubt about Optimus, MUX and Nvidia Advanced Optimus. For more in depth video details you can watch below video.
Note : Its in Hindi Language.