"It's been a while since Ubuntu could be called a leaner
alternative to Windows. While it's safe to say that it runs a bit
better on older machines than Windows Vista, its transformation
into a truly full-featured operating system capable of replacing
Windows in most situations has rendered it more bloated than other
less mainstream alternatives.
"However, one of the nicer features of Linux (at least for the
end user) is the ability to choose the windowing environment with
which we interact with the underlying OS. Essentially, we can
choose from any number of graphical user interfaces that suit a
particular situation. By default, Ubuntu desktop editions come with
the Gnome interface which works quite well, but is far more
responsible for the apparent bloat than the actual Ubuntu operating
system itself. KDE and Xfce are two other "desktop environments"
and can be installed as the native Ubuntu GUIs that make up the
so-called Kubuntu and Xubuntu official variants. Xubuntu is
generally considered to be lighter in terms of memory and CPU
utilization than either the Gnome- or KDE-based versions of Ubuntu,
but they don't hold a candle to LXDE."