my car computer is a p3 600mhz my original gateway purchased in 2000
has a 90w ps w/ onboard graphics
i can listen to tunes and gps streets & trips
or run wmp visualization no problem
seems to do the job
15" industrial lcd custom mounted to the dash
i think its 35w
plus a stock honda stereo probably no more than 100w
eh...it gets me by
back when i owned the vx i couldn't manage to make a difference mpg wise either using the computer or not