Have you compared with something else than Chrome? Otherwise it might be that Chrome is just very power hungry compared to Safari, but maybe Firefox is more efficient by now? Chrome has slowly turned into a monster on it's own, not unlike what they competed against initially when Chrome first arrived.
Safari use less CPU power than Firefox, chrome being the worst of them all.
It's even more obvious when watching video where safari will be 5 to 10 points lower than Firefox.
Harder to say when it's rendering page but the fact of the matter is that I tried both for years, Firefox always drain the battery faster.
>It's even more obvious when watching video where safari will be 5 to 10 points lower than Firefox.
Safari uses macOS for video so the points will be on macOS. Firefox uses it own internal video decoder. That is why image and video codec support on Safari is dependent on macOS upgrade not Safari.
Safari uses OS frameworks but they're called from Safari subprocesses and counted as part of Safari.
I can assure you, this is still true. I use Chrome when plugged in at my desk and Safari for everything else on the go. Chrome still isn't great on memory or battery life.