Lubuntu is advertised as lightweight and good for older hardware. The Dell is circa 2005.
Ubuntu 16.04 recommends 512MB (https://help.ubuntu.com/lts/installation-guide/s390x/ch03s04.html).
Lubuntu is recommending 1GB (http://lubuntu.net/).
I installed Ubuntu and the UI response seems to be very slow. I am tempted to try Lubuntu, but before I do, I wanted to ask if I should expect the same or a snappy response?
Bonus if you have installed both on your system and can compare the two. Trifecta if you have the XPS 400 running either Ubuntu and can comment