Laptop Questions

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 worse battery life.

To understand what a MUX switch does, you need to first understand how 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, and the discrete graphics (dGPU), Nvidia RTX 3060 for example.

The dGPU is more powerful, so it burns more power. This is not ideal in a portable device where battery life is important. Instead of using the beefy graphics all the time, when they’re not needed the lower powered integrated graphics are used instead. The dGPU is still there and ready to be called upon should it be needed.

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 Optimus at work, also known as MSHybrid.

The Optimus Bottleneck

When running a game, the frames might be generated on the dGPU, but they’re first send through the iGPU before reaching the screen. This means that in many scenarios the iGPU acts as a literal bottleneck, and this is why being able to disable Optimus results in a performance improvement in games.

I’ve compared 9 games with Optimus on and off here, but basically on average Optimus off gave a 17% FPS boost in these 9 titles. This is at maximum setting levels too, lower settings levels generally see an even higher boost.

Lenovo Legion 7 - Optimus Off vs On
Lenovo Legion 7 – Optimus Off is 16.7% Faster Than On

It depends on the workload though, games with higher frame rates like eSports titles typically see a larger performance increase with the iGPU out of the picture. Rendering workloads like V-Ray or Blender see next to no difference, as the task is basically fully offloaded to the dGPU for processing rather than frames being sent back via the iGPU as is the case in games.

What is a MUX switch?

A MUX (short for Multiplexer, often misspelled as “mucks” or “muc”) switch lets us 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.

A restart is required 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. They don’t show in task manager anymore, instead only the discrete graphics are available. This is much more like a regular desktop PC now, where the screen is connected straight to the high powered GPU. Gaming performance should now be improved, as shown above, but if you need to run on battery power the run time will be less.

Battery Life - Optimus On vs Off
Battery Life – Optimus On vs Off

In this example, Optimus on was lasting for almost twice as long as Optimus off.

MUX switch unlocks extra features

Additionally, it will now be possible to use extra features. With Optimus enabled, Nvidia ShadowPlay can only work within games for screen capturing. To use ShadowPlay outside of games with other software or just the Windows desktop requires the direct connection between the screen and Nvidia GPU – That is Optimus Disabled. Optimus disabled is also required to use G-Sync on laptops that have G-Sync compatible panels.

Does my gaming laptop have a MUX switch?

Great question! If it’s a model that I’ve tested then you can refer to this page to find out if it has a MUX switch. If your model isn’t on that list, you can find out how to check your laptop for a MUX switch yourself for all popular gaming laptop brands here. I also mention this in every gaming laptop review on the Jarrod’sTech YouTube channel.

A MUX switch is a preferable, if premium feature

Without a MUX switch, your gaming laptop is either stuck with Optimus enabled or disabled, you cannot change it.

Throughout the last year, gaming laptops with a MUX switch have definitely become more common compared to the year before, or the year before that.

Many high end gaming laptops unfortunately still do not have it. ASUS in particular have told me that they didn’t include it in mid range models like the Strix G15 Advantage Edition as it would increase cost, but then they also didn’t include it in their higher end Zephyrus M16 either.

Personally, I think user choice is best. If you want maximum gaming performance while running a game you can, then if you need maximum battery life at school or in the office you can do that too. The downside is of course that inconvenient reboot, but this may soon be a thing of the past.

Advanced Optimus – A Panacea?

The idea behind Nvidia’s Advanced Optimus is basically an automatic MUX switch, so no need to reboot to swap between iGPU and dGPU. Basically when you’re just using your laptop to browse the Internet, the integrated graphics will be in use, but then when you load up a game it will swap over to the Nvidia graphics only for full performance.

This is obviously much more preferable compared to manually rebooting your laptop every time you want to swap between them – especially if you have a Dell G15 5515, as you have to go into the BIOS to make the change, there’s no software front end option!

While Advanced Optimus sounds great in theory, in practice I’ve never personally had the chance to use it despite it apparently being available for some time now. This is kind of telling to me as a laptop reviewer that it may not be ready for prime time just yet.

Sure, there are some laptops sold with the feature right now, but I’ve heard from a number of large companies that they’ve had to delay their launch of Advanced Optimus. I haven’t been given a clear reason as to why, but I get the impression it’s bugs or other implementation challenges.

I don’t have a MUX switch, can I still bypass Optimus?

No MUX switch? No problem! You can still boost gaming performance by instead attaching an external monitor to your laptop. Just as long as the display output connects directly to the discrete graphics rather than the Intel or AMD integrated graphics. For more information on this topic, please refer to this video.

Hi, I’m Jarrod, a tech reviewer from Australia. I mainly focus on laptops, but am interested in all things tech related!

15 Comments

  • Timon

    Hey Jarrod, thanks for the great explanation and those who do not know better! I want to ask a question a statement I have been seeing a lot. Is the base Legion 5 considered budget as in things like ‘nitro 5 and tuf a5’ or more or less a lower midrange machine. Thanks in advance.

  • Mizumaky

    Hi Jarrod, nice summary!
    Although, the thing I was looking for was information about the option for selecting the GPU for the laptop’s display in Legion 5.
    I do not mean the “Hybrid mode” switch, but the “Dynamic display mode” switch (located at a special tray icon). There, with hybrid mode enabled, I can select either Automatic select, NVIDIA GPU only, or Optimus. What it says it does is change which gpu outputs to the laptop’s display on the go. Could that be advanced optimus?
    And could selecting NVIDIA only actually work the same as disabling hybrid mode?

    Maybe the tray icon was not visible by default, but I always enable all icons from the Nvidia control panel.

    The downside of this option I noticed is, that when I connect an external display, it automatically switches the laptop display to Optimus and prevents me from changing it.

  • Mizumaky

    If you still have a Legion 5 / 5 pro / 7 with you, you could try if you have it there. I have a regular Legion 5 (model 15ACH6H from 2021 with 5800H and RTX3060) and have it, so it makes me wonder whether all have them or that just this one is somehow special.

    As I have checked, it should indeed be Advanced Optimus:
    https://nvidia.custhelp.com/app/answers/detail/a_id/5097/~/nvidia-advanced-optimus-overview
    The settings can be found in the Nvidia control panel under Manage display mode.
    OR
    In the Nvidia control panel in the top menu at “Desktop”, there is a checkbox saying “Show Dynamic Display Mode”. Then, I can see an additional icon in the tray where I can set this too.
    (Hybrid mode needs to be enabled for it to appear)

    • Jarrod

      Advanced optimus is rolling out on many current models over time that don’t initially come with it, I just did a bunch of updates on my Legion 5 and can confirm I have this option. I assume the 5 Pro and 7 will have it too, I remember Lenovo telling me it was coming back when I had it for review they just weren’t sure when so I never mentioned it as a feature because there have been too many instances of stuff like that never eventuating.

  • Jon

    I’ve got the same Legion 5 (15ACH6H 5800h/3060 – Part No. 82JU002WUK).
    From recollection, the Dynamic Display Mode Tray Icon was on (by default) ‘out of the box’; due to getting notification popups from this, I subsequently disabled the tray icon in Nvidia Control Panel but enabled the GPU Activity tray icon, which I actually find useful as it shows when the dGPU is active.

    I had no idea that the Dynamic Display Mode is part of Advanced Optimus until I read your’s/Jarrod’s posts above.
    When ‘Nvidia GPU only’ is selected, after a brief screen flash/update, the other options appear the Nvidia Control Panel (additional display settings, like the G-Sync options, and also color settings). Also, as per the Nvidia page, there’s now 2 Displays shown in Windows Display settings.

    It’s quite a surprise to see both a MUX switch and Advanced Optimus on the Legion 5, as I’d understood that both were sort of ‘Premium’ features whereas the Legion 5 is said to be more budget oriented.

    • Jarrod

      It seems like advanced optimus updates are rolling out, so that’s good to hear it’s been added.

      Update: confirmed mine has it, I just did a bunch of BIOS and Nvidia updates so not sure when it added.

  • Jon

    I only got my Legion 5 last Friday and one the first things I did (after imaging the drive – before I even booted to Windows first time) was run updates; BIOS version GKCN40WW was installed via Vantage (I’ve since found & installed version GKCN44WW, which wasn’t yet available via Vantage, via the Lenovo site downloads).

    On the Nvidia site (https://nvidia.custhelp.com/app/answers/detail/a_id/5097/~/nvidia-advanced-optimus-overview) it states, under the Info about ‘Manage Display Modes’ in the Nvidia Control Panel:

    Automatic Select (Default)
    When the user selects this option and an application that is in DDS allow list is launched, an internal display switch to discrete GPU will be triggered. The display switches back to integrated GPU only when the last application that is in allow list, is closed.

    What’s the ‘DDS allow list’, I thought. Google searching “Nvidia DDS” brought results about texture tools and th like?!?!? However, it does appear that DDS means ‘Dynamic Display Switch’ from looking at the Razer site page about Advanced Optimus.
    What I can’t actually find is any details of creating/amending a ‘DDS allow list’ i.e. putting an application/game to ‘DDS allow’.
    Does an application that uses the dGPU which isn’t ‘DDS allow’ just use ‘standard Optimus’ i.e. the output still routes via the iGPU?

    Perhaps, an idea for a video – testing applications using ‘standard optimus’ , Advanced Optimus and with Hybrid diabled/Optimus off. Also covering the thing I couldn’t find – introducing the ‘DDS allow list’ (i.e. what it is) and also how to adds applications to this list.

    • Jarrod

      I’ll have a look into it but might be a while as I only updated today and found my Legion 5 could do advanced optimus, I’ve never used it otherwise yet so I don’t currently know too much about its workings.

  • Jon

    Forgot to add (before posting) in the post above.

    One thought I had regarding the ‘DDS allow’ list was….is it the same as Nvidia Control Panel, Manage 3D Settings – Program Settings and then selecting the dGPU for a specifc application? i.e. customising Optimus as per this page (https://nvidia.custhelp.com/app/answers/detail/a_id/2615/related/1/session/L2F2LzEvdGltZS8xNjMxMTc2NzE1L2dlbi8xNjMxMTc2NzE1L3NpZC9mVVRDaXhEVDJ5cGJPQTMlN0V4a1lmXzJuazNKVURRSGRKM3hwTVJwbGZMT1F0Um1XWWQ3VnBvRHlpc3VtZjBrJTdFZ0p1cll6UDREM0Z0MEI0TFB4SnRVOE5vNE9fZyU3RXozSGZQbzZEaGZHZXk2ZnN2Vk43VnViNDU5UHclMjElMjE%3D) from 2010!?!?!

  • Cody

    Jarrod, I love the channel and really appreciate all the work you do in research and keeping the community informed.

    Question semi related to this post- could you recommend a laptop for $2500 USD or less? I’ve watched dozens of hours of you, gizmo, Linus, Dave, etc. There’s so much information out there to sort through its hard to feel confident in a decision. Also, even just telling me your 2-3 most trusted brands would be a huge help!

    The games I will play most- Minecraft, NBA 2K, Skyrim, The Witcher, RDR2, the upcoming Halo.
    Also, I will be doing the vast majority of my gaming on an ASUS TUF 27″ 1440p display. So I wouldn’t be that concerned with the laptop not having a MUX.

    Thanks again, I look forward to your reply but also understand if you don’t feel comfortable recommending anything specific.

    • Jarrod

      The problem is that I don’t really keep track of laptop prices, outside of a couple of popular models I couldn’t even tell you any machines near that money right now without spending a bunch of time researching. You should be able to find a 3070 full powered version for $1800 or so, so I guess 2500 is likely 3080 territory which is honestly diminishing returns once you’re at the top of a product stack. Personally I think the Eluktronics Mech-15 G3 / XMG Neo 15 with 3070 is one of the best so would probably get that and call it a day.

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