Nvidia’s Optimus technology was designed to deliver graphics performance in laptops that doesn’t drain your battery but it has a potentially uncomfortable downside: you sometimes can’t use it with VR due to how it’s integrated into the computer. Generally speaking it works well, but any issues you experience may come down to how laptop makers implement it.
Depending on the computer manufacturer’s choices, Optimus can often mean you won’t get raw access to graphics power the same way you would from a discrete GPU. When you plug in a headset to the HDMI port of an Optimus-enabled laptop, the GPU is enabled seamlessly but ‘patches’ the output into your screen via the integrated display controller of your laptop.
This is great for your battery but frequently isn’t compatible with VR. When you come to trying to set up an Oculus Rift or HTC Vive you’ll likely notice you’re stuck in the lower-performing extended mode rather than ‘direct’ because the HDMI port is soldered to the integrated graphics chip, not the GPU.
Optimus is a technology that’s all-or-nothing, because it’s based on the hardware layout in your computer — but usually you can force it off when needed by changing a few settings. On some machines, however, you can’t disable it in the BIOS, and there’s no way to force all GPU processing to bypass the integrated GPU, so it’s worth checking before you buy.
You should find that most laptop vendors allow you to work around Optimus with a physical button, BIOS flag or otherwise which disables it. If you’re not, like in the case of Dell’s XPS 15, you’re stuck in a weird in-between GPU zone where you have a great graphics card but can’t fully leverage it.
There are some other edge-cases to be aware of here as well:
Here’s a quick, foolproof way to tell if the laptop you’re looking at could have trouble or not, related to Optimus based on this:
With Nvidia’s 10-series cards this is far less common, but it does happen occasionally so it’s worth checking before you buy so it’s not a surprise later. The technology Nvidia invented for Optimus is legitimately useful, but occasionally the vendor implementation is limiting.