What makes Lubuntu lightweight?

Question

I have been told that for a slower laptop I should use Lubuntu instead of Ubuntu. Before making the switch I want to know all of the cons and pros.

What about Lubuntu makes it more lightweight?

Answer 1

There are a number of factors, not just the window manager, it is a sum of the window manager, desktop environment, and your hardware.

For this post, I assume the hardware drivers (kernel) is the same across all versions of Ubuntu.

See - What is the difference between a desktop environment and a window manager? for a discussion on window managers vs desktop environments.

As a Desktop Environment, Lubuntu uses a light weight window manager, with little or no "special effects" or "eye candy". xfce, kde, and gnome, in that order, use more resources in your RAM and graphics card just to run the window manager + effects.

Also, as part of the Desktop environment, Lubuntu starts less programs in the background at login. You can see what apps are run at startup (login) on lubuntu , xubuntu, kde, and gnome by looking at startup in each DE

In general Lubuntu starts less apps, and thus uses less RAM at startup.

And the third factor is the default applications. Each DE has a different set of default apps for web browsing, text editing, etc. With Lubuntu these apps are lighter weight in that they use less storage and less ram when they run than similar apps in other DE. Sometimes the difference is small, but sometimes large.

For the most part, running a similar application gets about the same performance across DE. So firefox or libreoffice, to name a few, are going to run about the same on any DE. Lubuntu is faster in one aspect because it uses lighter weight applications and thus better performance from the apps themselves.

The only exception would be RAM. If you are low on RAM, your apps are going to start using swap, which will affect performance. In this respect, lubuntu is going to use less RAM at startup preserving as much as possible for apps.

See /desktop environments ram use or similar.

In general, for the average desktop user you are going to want 2-4 Gb of RAM. If you have less it makes sense to find an alternate to the heavy weight apps and change from firefox to an alternate. You can do this in any DE, Lubuntu selects one default set for you already as a start point.

IMO, to determine if Lubuntu is right for you you have to ask:

• Do you like the look and feel of the desktop ?
• Do you "need" any additional startup apps ? How easy is it to add if needed ?
• Do you like the default apps ?

Answer 2

Generally, there are many choices for any given function in Ubuntu. File management in the GUI can be done through any of at least three or four programs; office/productivity work can be done with several different word processors, spreadhseets, etc. Even the desktop manager and environment have multiple choices (Gnome, Mate, Cinnamon, Budgie, KDE, etc.).

Different choices take up different amounts of storage space, require different amounts of RAM to run, put more or less load on the CPU, and so forth. For instance, KDE takes more space and RAM and requires more CPU cycles for routine functions than XFCE. This makes XFCE "lighter" than KDE.

In Lubuntu, the stock install software has been chosen in general to minimize storage size, RAM requirement, and CPU load. This is what makes this flavor "lightweight" compared to, say, Kubuntu, which uses KDE and has lots of eye candy the user can turn on (especially in 14.04, which uses KDE 4; KDE 5 found in 16.04 has dialed this back a little, in my limited experience).

Beyond the DTE, the functional software in Lubuntu has similarly been chosen to be lightweight -- instead of LibreOffice, which is quite demanding, Lubuntu uses Abiword and Gnumeric for word processing and spreadsheet. They do the same work, generally, but spend less RAM and CPU time on cosmetics, and have fewer seldom used options (which simplifies the program and reduces its storage footprint).

All of this adds up to the difference between Lubuntu that will install in 16 GB and run pretty well on a 1 GHz single core processing with 1-2 GB RAM, and Kubuntu that's not really at its best in less than 40 GB, 4-8 GB RAM, and on a 2 GHz dual core (preferably more speed and more cores) -- and is helped a lot by a high end graphics card, as well.