Hi there. Version 1.4 of the [Desktop Entry Specification](https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html) added a new key, "PrefersNonDefaultGPU". It's an optional boolean key described as follows: > If true, the application prefers to be run on a more powerful discrete GPU if available, which we describe as “a GPU other than the default one” in this spec to avoid the need to define what a discrete GPU is and in which cases it might be considered more powerful than the default GPU. This key is only a hint and support might not be present depending on the implementation. On systems with NVidia discrete GPUs, render offload is controlled with three different environment vars as [documented here](https://download.nvidia.com/XFree86/Linux-x86_64/460.67/README/primerenderoffload.html). It's probably a good idea to just set all of them when the discrete GPU is requested. * `__NV_PRIME_RENDER_OFFLOAD=1` for Vulkan applications to enumerate the NVidia GPU first. * `__GLX_VENDOR_LIBRARY_NAME=nvidia` for GLX applications; tells GLVND to load the NVidia GLX driver. * `__VK_LAYER_NV_optimus=NVIDIA_only` ensures integrated GPUs are not enumerated *at all*. On systems with AMD discrete GPUs, exporting `DRI_PRIME=1` may be all that is needed, but [there may be pitfalls to doing it like that](https://github.com/flathub/com.valvesoftware.Steam/issues/559#issuecomment-815900530). On Xubuntu 20.04, the key currently does nothing, at least as far as I can tell since I have a laptop with Optimus. The most recent steam-launcher sets this key, and it is present in the latest Flatpak for Steam. If I start Steam from Whisker Menu and run a graphically intensive game, it chugs like it's on integrated. But if I set the requisite environment vars myself before starting Steam, the same game runs fine. Thanks for your time. 🙂