When I plug in my laptop (Asus EEE pc with brazos) it can't play a movie without lagging. When I unplug my laptop from the power socket, the lag goes away.
I'm a bit baffled by this because I expected this behavior to be the other way around.
I'm on the latest Xubuntu. Is there a place where I can extensively check the powerplans, as the default power manager is quite poor.
I presume this behavior is inconsistent with the settings for the power manager in your system settings? I found the same as you, that Ubuntu doesn't handle laptop power management very well "out of the box". I had to install
laptop-mode-tools
. So far I have seen much more typical power consumption without having to configure it.If you're just interested in seeing what's going on first, install
powertop
. That will show you what's consuming the most power and give suggestions on what options to turn on and off.