The PC port of Batman Arkham City was horribly implemented and littered with issues involving, DirectX11, Nvidia PhysX, and .NET.

If the pre-game launcher/menu launches (the launcher that displays, Play, Settings, View ReadMe File, Exit) go into Settings and disable anything related to DirectX11 and Nvidia PhysX.

If the following doesn’t work you may need to install an older DirectX version (DirectX 9 I believe) and/or edit a PhysX DLL file. Batman Arkham Asylum has very similar issues as well, I believe solely installing an older DirectX version fixes it though.

Take all this with a grain of salt because it’s been a very long time since I’ve played Batman Arkham City.

If I don’t alt-tab the game doesn’t break.

It’s likely the 560 driver on Wayland being the culprit here. Specifically resizing XWayland windows. You could try running nvidia-smi in a terminal and see what specifically is causing this VRAM spike.

Reports of excessive VRAM usage with the 560 driver on Wayland. See this for a potential fix. Hope it helps

https://www.gamingonlinux.com/ is a wealth of information, of which, I am not willing to let go, as it is a resource of current news that is very relevant to this “Linux Gaming” sub. So no; I will not stop linking https://www.gamingonlinux.com/ to this sub just because you got butt hurt.

RIP our wallets 😓

If you’re only going to pick Pop!_OS or Manjaro, I’d suggest you go with Pop!_OS. The Manjaro team has been very weird, and made some poor decisions in recent years. I’ve had a very good experience messing around with Pop on an Nvidia GPU.