Previously before, I didn't touch apps like GeekTool because I was afraid that it would slow down my system performance severely. (MacBook Pro 15" C2D 2.4ghz Late 2008) However, I have decided to use it as a clock on my wallpaper.
How much CPU % would GeekTool use? I only have the measly 2 hour battery for the MacBook Pro, so conserving as much CPU cycles as possible would be my aim.