Don't use Fasterfox. It tweaks many settings that frequently result in performance regressions. The default networking-related settings are set the way they are for a reason.
Performance has not been a complaint of mine, especially network-related. It's everything else. Almost like Firefox is optimizing for just shoveling as much CPU power and RAM as possible into it's gaping, bloated maw, not caring about anything else. Kinda like an old mail application from a startup I worked at. Nothing has ever matched how amazingly good it was at certain things it did (or even have similar features), but hot DANG did it just drink battery like its going out of style.
> Almost like Firefox is optimizing for just shoveling as much CPU power and RAM as possible into it's gaping, bloated maw, not caring about anything else.
Don't use a fork and don't customize your user.js. It is exceedingly unlikely that excess power consumption is caused by anything you can easily tweak. Instead report issues to Mozilla.