As a geek looking for a easy, well-maintained distribution of GNU/Linux, I've been using Ubuntu for several years, but also consciously trying to find anything that makes computing just that little bit greener. Ubuntu is supposed to be used in developing countries on reused hardware, but still comes with some quite bloated applications and two usual desktop environments: KDE and Gnome, with tempting bells and whistles that use a bit too much CPU. The latest long-term-support release, 12.04, also known as "Precise Pangolin", came out a week or so ago and is reputedly a big improvement, but I'm waiting for a few updates in July before really getting to grips with it. So the following tips apply to 10.04, lucid. Also note there are other flavours of Linux claiming to be "lightweight", WattOS, Puppy Linux and the Ubuntu variant Lubuntu.
I've preferred to use standard Ubuntu and install the LXDE package as a cleaner, simpler desktop environment. It's a little rough in some places such as menu editing, but seems to use less RAM and be less distracting. One thing that I've found missing from this approach is the power management features of GNOME that allow you to automatically suspend or sleep if you've accidentally or lazily left the computer on. Sadly, power management gets less attention than other development, like adding new features to things that probably work fine as they are (although developers have been looking at a few things that can be done to kernel parameters and there is a team looking at software efficiency).
The gnome-power-manager, even though installed with Ubuntu+LXDE, is not in the LXDE autostart. In brief, Debian packages that install autostarts into /etc/xdg/autostart/*.desktop are for some reason ignored by LXDE, so should either be symlinked into ~/.config/autostart/ or for privileged processes, put into the /etc/xdg/lxsession/LXDE/autostart file. So to get the computer to sleep automatically:
- Install the xfce4-power-manager package
- edit /etc/xdg/lxsession/LXDE/autostart (you can Alt+F2 and run gksudo gedit /etc/xdg/lxsession/LXDE/autostart)
- after the "@xscreensaver -no-splash" add @xfce4-power-manager
- In Preferences > Screen Saver (xscreensaver), use the "lock screen" option, but basically we don't want to use the screen saver.
- Run /usr/bin/xfce4-power-manager-settings and for convenience always show the system tray icon
- Under the AC settings. set sleep to the minimum, 15 minutes, and the monitor settings to a few minutes.
By the way, Windows Vista and Windows 7 have what is called "hybrid" sleep mode, which is both quick to wake up and doesn't lose data if you turn the power off at the wall, although it does use a little more power than hibernation for a few hours. No Linux distro I've come across yet does this.