That's really a question for Biff to answer...I know that he carefully chooses what goes into wattOS so that it uses less resources.
I can give you my personal experience though...
I've built my own system(s) from three different OSs to see which would use the least memory on an old computer that I have...I tried Debian, Ubuntu, and Arch...using Openbox as the desktop.
On the Ubuntu minimal cd, I chose the "Install your own software" (or whatever it's called) option rather than choosing a desktop.
On the Debian netinstall, I removed all of the checkmarks from the screen where you choose the desktop.
On Arch, I...well...installed Openbox.
Doing that on Ubuntu and Debian will give you just a command line screen when you first log in after installation...just like an Arch install. You then have to install
everything yourself...just like on Arch. To keep the Ubuntu and Debian builds as small as possible, I made a lot of use of the command...
sudo apt-get install
some-software-name --no-install-recommends
All three builds were basically the same. If I remember correctly, the Ubuntu build used the least amount of RAM (which surprised me). Debian took up slightly less space on the hard drive than the others. However, all three used basically the same amount of RAM and resources. I could tell no difference between the performance of all three. So, when Arch talks about how small their installations are, and they only install what is needed...it can also be done (and beaten) with other OSs. That's not to cut down Arch, because Arch is a great system. It's just that it's possible to do the same with others if a user knows what (and what not) to install.
All three used around 80 MBs of RAM at boot up. However, part of that was due to the fact that I didn't have to have a Network Manager since I use only Ethernet on that one computer. I also didn't install a power manager...which meant the screen would automatically turn off after 10 minutes of no use (which can be changed)...but that was fine with me on that computer. I also didn't install any update manager; I installed updates through the terminal. Just those three items will save a lot of RAM usage on a computer.
However, wattOS includes all of that and still uses little resources.
Which is why after all of my fun experimenting was over, I put wattOS back on it.
