Safari consuming too much CPU
Whenever I use Safari I soon hear my laptop's fan running, and Activity Monitor reports that Safari is using something like 134% CPU.
It happens every time I use Safari for more than a few minutes. It doesn't seem to matter what websites I visit, and I don't have to have lots of tabs or windows open. The culprit is Safari, not Safari Web Content. It's only the CPU numbers that are high; memory use looks normal. No problems with Firefox or any other applications. The problem started in the last month or so (possibly after the last Safari update?).
I tried disabling Flash and all Safari extensions; so far nothing helps. (I had only a couple of extensions anyway. I've never used ad blockers.)
MacBook Pro Retina display (mid-2015)
OS X 10.10.5
Safari 9.0.1
MacBook Pro