Are these implemented by dev themselves or are they available at engine level on all UE4 games? Is there a way to do this on other games that do not have this in-game config?
I'm not sure, but if you have an Nvidia card you can limit FPS in Nvidia Control Panel. I did that for Starfield so I didn't get the frequent 25-60 FPS swings.
Already tried that. No significant improvement over running at uncapped with v-sync (60fps).
baseline:
uncapped with v-sync (60fps)
result: running at 40% usage and 40C temp.
nvidia cp config:
capping at 20fps with or without v-sync (running in background)
result: usage jump up and down predictably between 20% and 50%, no temperature difference.
Clearly worse than capping it at game engine level since ES2 shows linear and stable drop in GPU usage. I assume this varies greatly on different game engine.