I'm having a really strange issue with my Macbook Pro Retina right now. For some reason, when using Firefox my CPU percentage is sky rocketing over 100% and the fans are running like crazy. It only happens on certain sites so I'm not sure if it's some kind of problem with some scripts or whether ads are causing it to go like this, but it also happens when watching videos. Even when I'm casually browsing it'll be running at around 60% and idk if this was normal before but it certainly doesn't seem so? I've disabled Flash for now, but it's still happening regardless. I'm all up to date on the latest Firefox, and I only recently upgraded to El Capitan a couple of days ago so I don't know if it's related to the new update, but Flash was causing problems previously anyway. I've tried running it in Safe mode and the problem still persists. The only extensions I have running are AdBlock Plus and LastPass, I also have the following plugins - Shockwave Flash (disabled), OpenH264 Video Codec provided by Cisco Systems, Silverlight Plug In, Widevine Content Decryption Module provided by Google Inc (which came with the latest update?), Default Browser Helper, and Sharepoint Browser Plug In. I have no custom themes or anything else. Is there a solution to this? I was having issues with Safari before so I'm kinda loathe to go back to it, and Chrome used to cause problems for me with Flash Player too, so I don't know what to do at this point. Any ideas would be super helpful Thanks.