optimization – What video settings make a game portable over different level computers?

I’m making a videogame paying attention on optimization of texture, material, meshe and so on. I’ve kept a good level of quality while having a relatively high and stable frame-rate but I don’t have the possibility to test it on lower level devices.

What settings should I let players change to make the game less resource-eager? Of course, every setting make the game performe better but I would like to know what’s the “must-have” talking about performance settings.

Talking about Anti-Alyasing, texture quality, frame-rate limit, VSync etc.

And what settings make the players more happy if they can manipulate it? Not necessarly related to performance.

Talking about Blur, Vignetting, etc.