SDDM vs. GDM – Which Desktop Manager is for You?

Evan Gower July 20, 2019

Display manager or “login manager” is a tool that starts your system’s display server. You shouldn’t mix up the desktop itself and the display manager, as the latter is responsible only for accepting your username and password and displaying the username.

SDDM vs. GDM - Which Desktop Manager is for You?

Most of the work that the display manager performs goes unnoticed, and you’ll often only see the “greeter” (login window) part of the tool. This is why it’s not always easy to pick the best one.

In this article, we’ll take a look at two very popular desktop managers, SDDM and GDM, to help you decide which one suits you better.

What Is GDM?

GDM is Gnome’s default display manager and it’s compatible with X and Wayland. With GDM, you can use the X Window System without the need to edit the config file or perform any actions in the command line. For some, this is a better choice than X’s default XDM display manager, which requires you to edit the configuration.

This display manager has some great features. It supports automatic logging, custom sessions, logging in without a password, and hiding user lists. Until the 2.38.0 version, GDM supported various design themes. However, all the later instances do not support the feature.

The program also has a set of interesting components. For example, chooser is a tool that chooses a remote host to manage a display remotely on the attached display. It also has a pluggable authentication module (PAM) and X Display Manager Control Protocol (XDMCP)

It’s important to note that Ubuntu recently completely switched to Gnome, and uses the GDM3 desktop manager by default. If you plan on using Ubuntu, it’s probably best to use GDM as there may be more development efforts to make it as compatible as possible.

gnome

What Is SDDM?

SDDM is a recent display manager that is also compatible with both Wayland and X. KDE, an international free software community, picked SDDM out of all other display managers as a default display manager in KDE Plasma 5.

The fact that KDM chose it as their own display manager proves SDDMs reliability. Besides KDE, Fedora, and LXQt, developers also chose SDDM as a default display manager.

This software is compatible with QML theming. While this is usually an upside, those who aren’t skilled enough with QML may find it difficult to customize the interface. However, the other configuring options are straight-forward.

To configure SDDM, you just need to edit a file (etc/sddm.conf). Editing this file allows you to enable or disable automatic login, decide which users will appear on the login window (greeter), pick a theme, and turn on the Num lock. If you’re a KDE user, you can find an SDDM-config-editor in the system settings which can make these modifications easier.

sddm

GDM vs. SSDM: Head to Head

Both GDM and SSDM have X and Wayland support and are reliable display managers. One is trusted by Ubuntu while the other gets the nod from KDE, Fedora, and LXQt.

When it comes to features, SSDM might have a slightly better user interface. It provides support for videos, GIF files, audio, and QML animations. GDM’s user interface is much simpler and integrates nicely with other Gnome distros, but lacks the aesthetic.

On the plus side, GDM is much easier to customize. You just have to know which files are customizable, and you can do a lot with it. It’s easy to change between environments, but you always have to use Gnome if you want it to work well.

Also, GDM will work well with any desktop, which is not the case with SDDM. This is because SDDM doesn’t launch the Gnome keyring when you log in, while GDM does it by default.

Verdict

Overall, SDDM is currently a bit better rated than GDM, but there are no big differences between the two. It mostly depends on how skilled you are in a certain markup language (QML in SDDM’s case) and whether or not you prefer an easy-to-customize manager (in GDMs case). Both of them work very well and are the default graphics display managers of some of the most popular Linux distributions.

So, which one gets the nod from you and why? Is it SDDM or GDM? Share your picks in the comments below.