Not for me. The kid of my sister would want try a Linux distro on a pc with 512 MB of RAM. The CPU, I believe, it's a Pentium III. Which is lighter between Lubuntu or Xubuntu ? I'm afraid that he all the same will not go much far.
Lubuntu is based on LXDE, which uses Openbox as a window manager and a small suite of applications to dress Openbox up into what we typically classify as a desktop environment. XFCE uses xfwin as its window manager which includes a compositor and a number of features, but at the expense of memory, cpu, and gpu usage (the last assuming you use the compositor). LXDE is a little more stickshift. Unless LXDE has come a VERY long way, if you want to get creative with how openbox works, you will need to edit the rc.xml file. Everyone complains about XML, but even with no experience I found it pretty easy to figure out. You can easily get Openbox to run bash scripts, python applications, conditional if/then statements, etc, whereas xfwin is significantly more difficult to accomplish such things. I use Openbox on Arch and have for about 7 years. I have never once had it break, nor has it ever had any changes that broke my existing configuration. It can be dressed up with compton (a compositor), various themes, and various utilities, or it can be used as it comes. I mention all of this because you might want to consider what your priorities are. Despite being lighter, Openbox is actually more powerful than xfwin overall, but at the expense of an easy setup. Xfwin and XFCE is still pretty light, so if you want all config options to be GUI based and place an emphasis on ease of setup, you should give it a try first- any hardware made in the last 8 years will fly with XFCE in use. If you have older hardware, want endless tweakability, or are just a minimalist, Openbox is hard to beat.
Just to nitpick, it's xfwm4 not xfwin. Lubuntu comes with an Openbox session. In other words, you can even avoid LXDE. I'm not sure there are significant differences in resource usage but the plain Openbox session is quite unfriendly initially. But once you get past that, it's fun.
Thanks for all your answers. I'll say to my sister son to try all these solutions. He'll see what is the best for his pc.
I'd go for XFCE. Although LXDE may be the lightest, I really don't like how it looks, how to customize it, etc.
If you have a very old PC - Bodhi Linux's Moksha Desktop will run smooth and fast on it. Its a stable version of Enlightenment.
I had tried LXDE at one point and out of the box there is no way to change the volume. Tried to add that capability and it was one search after another with no results though I'm sure that can be done - its pretty bare bones not to have that to begin with imo. There is a point of diminishing returns though that most likely differs from user to user.
I recently tried them out both on about 6 year old hardware (low spec AMD dual core). As Anonframe1 mentions I did not feel much difference in performance and Xubuntu was easier to install and tweak (I got both Firejail and AppArmor working without Linux knowledge). So it was ease of tweaking, looks and security which made me choose for Xubuntu (over a littl performance gain of Lubuntu).
PC-BSD's native Lumina Desktop. Its matured considerably and has been ported to various Linux distributions. Its intended to compete with LX-QT in the lightweight desktop environment department.
