I am looking for an Ubuntu version that consumes less Memory and CPU. I have read both Lubuntu and Xubuntu (The homepages, wikipedia, phoronix and other sites comparing both). But from experience, which one uses less memory and is less CPU intensive. I need to install them in very old hardware and want to persuade the owner of the hardware of the benefits of Ubuntu.

in this case I want to install 11.10 or 12.04 when it comes out. How are each behaving in those versions?

The 2 PCs I will be installing either Xubuntu or Lubuntu are:

Granpa PC:

CPU - Pentium 2 450Mhz
Video - 16MB
Used for - Documents and Internet. No listening to music, no looking at videos. Just using it for document writing.

The other old meat:

CPU - Pentium 3 550Mhz
Video - 16MB
Used for - Documents and Internet also but they want.. or maybe they are wishing for it to use it to see movies and listen to music. This one has internet. The other one does not.


Wanted to update this question with the test results for over 8 months worth of using Lubuntu and Xubuntu. When it comes to very old hardware, am talking about 64 MB, 128 MB or even 256 MB of RAM computers, Lubuntu is better than Xubuntu when comparing Memory usage. When it comes to CPU usage, both are the same.

This will not improve I/O Disk performance which will be the bottleneck for old computers. Also the difference in performance between Xubuntu and Lubuntu is about 10% to 20% percent in memory usage. Again, CPU usage is the same.

Now, when it comes to how responsive the Desktop is, LXDE (Lubuntu) has a much better response time than XFCE (Xubuntu). I would say about 50% or just simply noticeable to the eye. Lubuntu is similar to how Windows XP looks while Xubuntu is more like how Gnome 2 looked.

The computers (The old ones mentioned here) and 2 more are still working in excellent conditions thanks to the Ubuntu family. I also want to add I am using 13.10 for both distros.

  • for grandpa pc i recommend puppy linux, in the other you could try puppy too or xubuntu, i haven´t lubuntu experience
    – user165407
    Jun 8, 2013 at 1:20
  • low amounts of RAM is always worrying, I would really really encourage you to install more RAM if it's possible.
    – Alvar
    Nov 7, 2013 at 20:32
  • 1
    Hi Alvar, well in this cases the type of RAM is DIMM PC100 and PC133. Very difficult to find memory like that nowadays. Not only that but, except for one, they all have their memory slots used already (No memory slot empty to add more RAM). Nov 7, 2013 at 20:56
  • 1
    Even Porteus would require a minimum of 256M for a GUI, but only 40M for a CLI. While it's possible to browse the internet and edit documents via CLI, I doubt Granpa would enjoy the experience.
    – Elder Geek
    Mar 2, 2015 at 17:47
  • 1
    Appreciate the update! :) Not sure if things have changed, but the I/O performance is something I hadn't considered yet!
    – Cardin
    Apr 4, 2018 at 2:36

7 Answers 7


Your case studies are indeed challenging.

Take your Grandpa PC

Pentium 2 and 64Mb RAM.

Lubuntu minimum requirements are 128Mb if using the alternate installer - 256Mb for the Graphical installer.

The recommended RAM is 384Mb just to run the LiveCD.

Therefore - I'm afraid, you will not be able to install a graphical environment on Grandpa PC. At best you might get a text only "server" type install via a minimal ISO - i.e. you need a minimum of 64Mb to run the minimal CD.

The "old meat":

That is more promising:

Pentium 3 with 128Mb RAM - you should be able to squeeze on Lubuntu via its alternate CD.

However the minimum requirement for Xubuntu is 256Mb with 512Mb as a recommended RAM size.

I've experimented with various "low" RAM installs. I've never tried 128Mb - but in general, I install from a minimal ISO CD and install various components manually - for example, SLIM, LXDE with apt-get install --no-install-recommends to ensure no excess packages are installed.

Typical packages you should look out for if you go this route are described in the linked question below.

Stick with a lightweight browser such as midori - abiword should be ok for wordprocessing.

Flash and general movies will struggle with your video card. However playing music should be fine (see below)


  1. https://help.ubuntu.com/community/Installation/MinimalCD
  2. How do I install LXDE / Lubuntu?
  3. Lightweight music player
  • +1 and many thanks because of the abiword and midori. They will help a lot. Also the links are very good indeed. I know this are very tough cases and I also am amazed that those PCs are still alive. Mar 12, 2012 at 23:13
  • You may want to look at DSL linux for your Grandpa's PC. That's one of the lightest ones I know...
    – John
    Jan 20, 2014 at 22:17

In my experience there are a few things to consider.

First, and most important, do you (or your users) like the interface ? It makes no sense to "force" xfce or lxde on them. So, ask for their input on this.

Second, for the most part, the window managers all use about the same in terms for RAM and CPU. The caveat here is you need to compare apples to apples, if you enable 3d / special effects you will take a performance hit.

Most of your resources are taken by services or applications running in the background. To save on resources, disable as many as possible (do you use Seahore, VNC, etc). run gnome-session-properties and disable as much as possible.

Data: On my netbook ...

Gentoo + Openbox - When I first log into openbox (not LXDE), it uses 70 Mb RAM.

Ubuntu 12.04 - Unity 2d - Uses 300 mb RAM

With that said, firefox runs at about the same speed on both window managers.

So are all the bells and whistles of Ubuntu Desktop worth 200 Mb ram ?

Answer to that = personal choice.

Test it for yourself in Virtualbox or KVM, give your guest 512 Mb RAM, boot the live CD.

  • You have several good points there. In this case, they don't care about 3D effects or any effect for that matter. For the type of interface they also do not care if it solves the problem of a slow PC. But again, very nice points here. Mar 12, 2012 at 22:15

I would install bare console Debian, then with apt-get will install incrementally some window manager like OpenBox (it will install X as dependency)

Then will check how it is, if i need taskbar icons etc...


Upon the comparison made on vs. wiki Lubuntu is lighter and more efficient on old and low hardware systems. So on a Lubuntu vs. Xubuntu struggle, apparently Lubuntu is the winner.


For the 64MB machine, I suspect that only Puppy Linux would be usable, not any of the *buntus. Puppy Linux worked well for me on a thirteen year old Toshiba laptop.


Luis - you mentioned the first machine would be used for document editing. How will they save their files? To USB? This is something to consider because such an old machine could die at any moment. Would it be better to let them edit documents online somewhere like Google Docs or Microsft Skydrive? In both of those cases, a "modern" browser is necessary.

  • +1 because you are right about the dying part. Nice idea about Google Docs. Thanks Mike. Mar 30, 2012 at 15:00

Lubntu is better and faster. If your PC is too old, you will still have problems, Lubuntu is twice as fast and good as Xubuntu by my testing.

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