I have recently updated my browser to version 87...unfortunately I had to revert to version 85.0.2 because the browser pegs CPU every time there is an advert on Youtube. Doesn't matter whether I let it play in its entirety or skip it after the mandatory 5-second mark. I have tried running FF without addons, did not make a change. I tried opening a single window with a single tab...no result. Can you fix it in some kind of micro patch? I'm running W8.1 on i5 6600K clocked at 4 GHz with 8 Gb RAM in a dual channel.