I disagree, XP, to be useful with all of the fixes and service packs applied, running software that has also had fixes and service packs applied does NOT run on 11 year old machines. It needs at minimum 768MB of RAM, 1GB to be comfortable. Not many machines had that 11 years ago.
To run it on an 11 year old machine you need to either disable some functionality or upgrade the machine. You can do the same with Ubuntu.
I have not seen an out of the box XP SP3 system running in less than 512MB without major complaints from the user. Microsoft can claim 64MB minimum requirement still applies, but reality shows it is simply not true anymore.