Let me start with an absolute truth: Linux can run on older hardware, even as old as Intel 486 processors. Thinking that we are not able to see them around nowadays (except at museums), but also thinking that there are Pentium III computers around, we can find a distribution that can run on this hardware configuration and squeeze the remaining life most out of our older computer.
In fact, Linux is not slow. The all-in-one desktop environments like KDE and Gnome (sometimes accused as “bloated desktop environments” in some forums) make people think that Linux is slow. If you configure your Linux distribution to not boot into the graphical desktop, you will immediately see that the computer boots faster and the time you reach the login prompt is way shorter than the time you reach your desktop. A significant amount of time is spent on the graphical desktop initialization.
We will continue our article based on this idea. We will go and choose two Linux distributions that can be considered the best Linux distributions for slow computers, both of which utilize the lightweight XFCE desktop environment.
As you have guessed from the name, Xubuntu uses the lightweight XFCE desktop environment instead of Gnome (in Ubuntu) or KDE (in Kubuntu.) Do not think that XFCE is less capable compared to Gnome and KDE. Instead you can run the same programs in your Linux computer and enjoy a better performance. Your key applications such as your web browser, Microsoft Office compliant office suite, instant messaging, photo management, and multimedia applications will all be installed.
Since Xubuntu uses Ubuntu repositories, you will be able to access all the programs that are available to the Ubuntu community. This means, if a program that has a functionality you need is not installed by default, you can simply go and install it from your package manager (or the famous apt-get command.)
Xubuntu comes on a CD and requires 256 Megabytes of RAM and 1.5 Gigabytes of hard disk space. It follows the standard Ubuntu releases and is updated frequently in line with Ubuntu.
Fluxbuntu is all the same, but uses the Fluxbox desktop environment instead of XFCE.
Puppy Linux is a rising star in distributions oriented for slow computers. The download size is 93 Megabytes and it is capable of being used as a live distribution that can run from a CD or USB stick. Like other distributions, you will have your office programs, web browser, and instant messaging applications readily available.
Puppy Linux has its own package manager and you will be able to install additional applications using the Puppy Software Installer. The program is intuitive and very easy to use. Therefore, I do not expect you to have problems.
As in Xubuntu, Puppy Linux uses the lightweight XFCE desktop environment.
Linux is all about choices as everybody says. You can easily find a distribution that suits your needs, such as an Ubuntu or openSuSE with all the Compiz effects enabled or if you do not have such a high-end configuration you can go for Xubuntu or Puppy Linux. At this point I can say that they are two best Linux distributions for slow computers.
As a Bright Hub tip, if you have installed Ubuntu and having performance issues, you can simply issue apt-get xubuntu-desktop and select the XFCE desktop when you log in next time.