"The major difference came at the time of loading the desktop, where Xubuntu used almost ten times as much memory. Yes, almost 10 times (well, actually around 9.314705882 times). So why? Where does all this extra usage come from? Essentially it is due to Xubuntu's use of numerous services from the Ubuntu desktop environment, such as their graphical package manager and updater, network manager, power manager, proprietary driver manager and more, all of which use more memory. Debian on the other, chooses to use the software which comes with Xfce by default.
"So, does that mean all is lost? Not at all! The comparison was between two end products - Xubuntu 9.04 and Debian 5.0.1 Xfce. As you can see not all products are created equal, but there's no reason as to why we cannot perform a more customised Xubuntu install. This would allow us to pick and choose the packages we want, therefore making it more lightweight. DistroWatch has previously published a few other similar HOWTOs, one for minimalist Ubuntu 8.10 and another for minimalist openSUSE 11.1. If your computer is a desktop machine which sits on a local network, why does your system need a resource-hungry service like NetworkManager? If you don't have any hardware in your machine which needs proprietary drivers, then why have jockey installed? As you will see, Xubuntu can be just as lightweight as Debian!"
