[Linux/Ubuntu] I need to run some pretty intensive calculations. How can I load a very minimal Gnome session for that purpose ? The idea is to create a new user, whose session would load only the minimum necessary.
My script runs in Python with various libraries, but it won't run without an X session because it uses Pylab. It is very CPU intensive and uses lots of RAM too because the dataset is huge.

I know how to add a user to my Ubuntu installation. Once I've done that, what do I do to disable loading of most of the usual services for this user's session, but not for the main user ?
or should I try to use a lighter desktop environment for that ?

I welcome any piece of advice on that ! thanks.