Question about pixmap as a DA buffer

[Diego Jacobi <jacobidiego gmail com>]

Hello.

I have read that Pixmap are stored on server side and so, they are
slower to be used like a double buffer.
Instead i use in my applications just a cairo surface, but i am
reading on the oficial GTK tutorial, that it is using a pixmap as a
buffer.

http://library.gnome.org/devel/gtk-tutorial/stable/x2928.html#AEN2930

So, ¿¿ is it or is it not a good idea to use a pixmap as a buffer ??
I am not an X expert, nor GTK. So i dont understand the implications
behind each one

If no, why the tutorial teach to noobs to use a pixmap?

Cheers.
Diego