With a handful of websites loaded in Safari, Flash-based ads kept the CPU running far more than seemed necessary, and the best time I recorded with Flash installed was just 4 hours. After deleting Flash, however, the MacBook Air ran for 6:02â€”with the exact same set of websites reloaded in Safari, and with static ads replacing the CPU-sucking Flash versions.
Get rid of Flash and add two hours of battery life. Not only that your CPU is free to do more important things than to keep Flash ads going on your browser. Of course, you can try AdBlock and block ads completely but keep Flash for when you want to view Flash-based videos. My little machine is Flash-free, i.e. slow-down-free.