Why does Google Chrome Helper spike my CPU? This has been happening on and off since I switched to a mac at work. Google Chome Helper occasionally runs my cpu into the red and has the fan spinning madly.  Sometimes restarting Chrome fixes the problem, sometimes not. Eventually it always surfaces again.
The problem, in my case, seems to have been one of the tabs I always have open runs some crazy cpu-intensive plugin for ads (I suspect Grooveshark, but am not positive).

The fix was to go into Chrome settings (settings > content settings > plugins) and choose Click To Play.  By default Chrome runs all plugin content as soon as the page is loaded - regardless of what is is, or how much memory it takes.