Under linux (normal web browsing, coding, etc.) I get around 5 1/2 hours. With windows that goes up to around 7 hours. I think much of the windows battery saving comes from the very low power mode it switches into automatically when you unplug the laptop. This mode can be a little annoying though as it powers down the cpu and you can't do basic stuff like watching a high quality video smoothly, etc. As far as I can tell under Linux the power saving mode is much more conservative.