This should be a native thing in any browser.. Is it possible we can get whitelist for some pages where things can break.

This does disable CSS transitions, but it also breaks some commonly used websites such as https://login.live.com/

Very helpful on older hardware, keeping my laptop usable!

I've been using this addon for 2 months and it works quite good. In the majority of sites (I would say 90%) where Firefox lagged before, Firefox became responsive with this addon. In the end I see a big change.