I disabled the web clipper extension in safari after noticing it was the cause for my high cpu usage and following an article response from Apple. I approached the matter by disabling recently installed extensions - starting with Evernote Web Clipper at the top of the list. Presto - excessive cpu usage for Safari no longer an issue. https://discussions.apple.com/thread/3190569 Your problem now also explains why my battery from 'fully charged' was depleted when I opened to use it this evening. I really hope it hadn't kicked the fans on whilst it was stored in my leather case. I've only just adopted the basic/free version of Evernote to give it a whirl but to me this has put me right off and reminds me of all the bugginess and issues I was having with my previous windows dell PC never sleeping correctly. Let me tell you that sort of behaviour will KILL your laptop battery as it did with my previous machine if you laptop is a. not be sleeping when it should be; in a confined space e.g. laptop pouch, b. running hot with fans on; and c. completely depleting the battery, resulting in accelerated wear. Not going to risk going through that again with my new machine.