I have an HP all-in-one 1300 printer at home which I hardly ever (almost never) use. I have lately been noticing that my MBP takes longer to start and the system is not very responsive for some time after a startup. So I decided to find out what the problem was and I think I did. As soon as I got rid of the hp drivers and software, the system is flying again. 28s from power on to the ready to use system. With HP installed the top bar took longer to appear and the icons on the right of the bar took about 2 seconds to come out. Now it's basically instantaneous. I also noticed that the battery time improved, well, at least the remaining time on a fully charged battery improved.