Optimus vs NVIDIA GPU Only – Advanced Optimus and dGPU Settings Explained

Gaming laptops have two graphics cards onboard. One is the powerful one for gaming – the dedicated GPU, or dGPU for short – and the other is the low power one built into the CPU itself – called the integrated GPU or iGPU for short. For the sake of battery life, the iGPU is the one that runs your displays basically any time you aren’t gaming, and the dGPU is literally turned off. When you fire up a game though, the dGPU takes over, and renders your game as fast as it can. The problem with having two graphics cards connected to one display is a bit of a tricky one to solve though. NVIDIA came up with “Optimus” over a decade ago now to do just that. Basically, the dGPU’s video signal was routed THROUGH the iGPU, and then to the display. Optimus would control which GPU was the one doing the rendering. 

The problem with that design is that it’s a massive bottleneck. It adds latency since the game’s frames need to pass through the iGPU before being displayed, and can sometimes even limit outright performance too. That isn’t ideal – and the problem there is that even if you go into device manager and disable the iGPU, it can’t be fully disabled as the dGPU needs to pass its frames through it. 

Happily, laptop manufacturers started using the solution, a MUX switch. That’s MUX as in multiplexer – you can think of it like physically moving an HDMI cable from the motherboard IO on a desktop to your actual graphics card, and back again, every time you launch or exit a game. That switches between the two GPUs, and thanks to NVIDIA embracing that design with the newer “Advanced Optimus” tech, it’s a seamless switch. You really don’t notice it changing over at all, and now you get all the benefits of basically either not having a dGPU, or not having an iGPU, because the two are no longer connected to each other. 

So what’s this video about then? Well NVIDIA actually gives you an extra setting here. Under “Manage Display mode” in the NVIDIA Control Panel, you’ll find three choices: Automatic; Optimus; and NVIDIA GPU only. Technically speaking, “Automatic” should really be called Optimus, and “Optimus” should be called iGPU only, but really we’re looking at the top and bottom options. The top one is standard Optimus – well advanced optimus still – and the bottom just disables the iGPU. I’ll start off by saying that for most people in most situations, leaving this on “Automatic” makes the most sense. For all intents and purposes, this is the best option for most people. But, if you’re an enthusiast and want the best experience and don’t mind a few tweaks and drawbacks, then this is for you.

There are a couple of reasons why you might want to switch to NVIDIA GPU only mode. The first is freeing up some power for your CPU. Now this isn’t really a big deal as gaming doesn’t tend to really push a CPU to anywhere near its power limits, but it’s the same principle for buying a KF desktop CPU from Intel. It means you have a touch more power on hand to give to the CPU, or thanks to Dynamic Boost, maybe even the GPU. That can mean you get a tiny, tiny little bit more performance, but let’s be real, this is a more paper benefit than anything.

The other, more useful reason is that Optimus sometimes gets which GPU to use wrong. I’ve booted up games and it runs horribly, then I switch to dGPU mode and hey-presto it’s running great. This can mean significantly less performance in games randomly, as sometimes it does pick the right GPU, but when it doesn’t it is a massive pain. It can also mean worse latency – I found on the XMG Pro 15 that with Optimus enabled I was getting over 10 milliseconds of on display latency, but with the NVIDIA GPU only mode that dropped to just 3 milliseconds. Literally cut by almost 4x. That’s a pretty big incentive to use the dGPU mode, right? 

Well, yes, but there are some costs, specifically battery life. The very reason laptops have two GPUs is because one is much, much more efficient than the other, and so disabling the efficient one is going to cost you in battery life. You can, of course, just manually switch to the dGPU mode when launching a game, then switch back when you close it, but having to remember to do that would get pretty annoying – and worse, as the Aorus 16X demonstrated so nicely for us with their automated version of exactly that, when you switch between optimus and NVIDIA GPU only, it often hangs the whole system for 5 to 10 seconds, both ways. Launch a game? Cool, your system is frozen for 10 seconds while it does the switch. Close a game? Locked up for a bit. It’s pretty annoying.

So, unless you are having issues with games performing poorly on your gaming laptop, personally I would just leave it on automatic. If you want to spend the time to get the best possible experience, or are having issues where games are suddenly running like trash, maybe give the NVIDIA GPU only mode a go.