Thanks for advise Ashley and tim. I tried doing some dynamic performance stuff last project by the following
> Every tick.
>> If FPS is lower than X turn off feature.
>>If FPS is higher than Y turn on feature.
However, this can cause performance ping ponging. So I also tried
> Every tick.
>> If FPS is lower than X turn off feature.
However, any slow down of course turned the feature off. So then I pushed the FPS to an array every tick and took an average FPS over X records, BUT during that period any bad performance can be seen. So I guess I could still use this method but display an overlay to hide bad performance.
There is something that has been imagined by a prophet a long time before, something marvellous, amazing, we, simple humans, call it the "Option menu", you should try it, there are graphical options to help people with devices that have a hard time with the graphic aspect of the game, and also sometimes options to lessen the amount of CPU needed for, lets say, the environnement or the sounds effects.
(Sorry for the overcreative way to say "you could let the user choose the quality and other things himself so he can have the best experience", but it seems people have a hard time thinking about including options in their game sometimes.)