Power consumption test. Safari 10+ watts, Chrome 50+ watts
twitter.com
twitter.com
Result: There was a 3 Watts (roughly) difference favoring safari.
That benchmark is more interesting to me.
(I discovered this quite by accident when investigating why my display would flicker when starting/quitting Chrome if I was also using f.lux.)
Since it is a single tweet, we cannot really take it as seriously as we could if they explained their methodology and showed that it was repeatable.
[0] "Conventional IPS" slide: http://www.j-display.com/english/technology/jdilcd/pictureq....
And don't most Mac portables ship with h.264 hardware acceleration?