Posted on 2007-10-09
I just got back from the GNOME Boston Summit, and spent quite a few hours traveling with my laptop at hand. This brings up the question whether Compiz Fusion is suited to be run on a laptop on battery power or not.
My current laptop is a HP Compaq NC4010, with an ATI Radeon IGP video card (IGP means no discrete video memory, among other things). Due to the age of this card, it is necessary to run X in 16 bit color depth to get fluent animations, which is something I recommend everyone with slightly older cards do.
As for battery usage, there are two concerns; Whether just having Compiz running, doing nothing, enables features on the video card that draws more power, and whether what Compiz and the general Composite environment it self causes more wakeups and thus higher power consumption. For the first question I don't have any real answer, I would assume this varies from card to card. The second is fairly easy to answer though, with the help of Powertop (http://www.linuxpowertop.org/). It seems to me that compiz in general doesn't really cause much extra power consumption. Ironically, the feature in Compiz Fusion that causes the most wakeups is the mouse polling in eZoom, so when I'm traveling I set the mouse poll intervall to 500, which results in far fewer wake ups, but also in an almost unusable mouse which only updates twice a second. For me, that's not an issue because I don't use the mouse that much while on the road.