Thanks to Windows 8 and Valve, GNU/Linux may finally become a first class citizen for the gaming industry. So which desktop should be your preferred for Linux gaming? I will answer that question but first see how different is KDE when compared with it's cousins Unity and Gnome Shell.
Martin Gräßlin, a lead KDE developer, addresses some queries around a topic bugging Gnome and Unity users - the fallback mode. I recommend reading his 'abridged' post. Here I am picking the points that I found interesting for our readers. The questions is: will KDE retain the fallback in 4.10 and after?
The long and short answer is: no.
Because KDE Plasma workspaces don't have the fallback mode the way Gnome of Ubuntu have. KDE teams made some standard based future proof decisions which keeps it out of such mess. KDE still maintains that - they follow standards instead of slapping patches on things to someone make them work.
So how different is KDE's window manager? As Gräßlin explains,
The main difference is that our window manager (KWin) is able to act as a non-composited, XRender based compositor and OpenGL (ES) based compositor. This means that we do not have to maintain two window managers in order to provide non-composited setups.
Another major difference as Gräßlin points out is that KDE's desktop shell is not "a plugin to the compositor but a separate application running in an own process." The benefit of this approach is that it allows you to use the desktop shell with a completely different windows manager. He then takes us back to the history classes explaining the decisions KDE teams mde when Plasma was being developed.
Back then OpenGL based compositing had been a rather new topic (I think I first heard about Compiz in 2004 or 2005) and it had only been possible with the binary blobs and hacks such as Xgl. The Intel hardware back then was not powerful enough and drivers were lacking, too. With other words: going an OpenGL-based only path seemed not feasible at that time and consider that the fallback modes in Unity and GNOME Shell got only removed in late 2012/early 2013. This is more than half a decade later – an eternity in IT. Also KWin did not enable compositing support by default till 4.2, so the first releases of KDE Plasma were non-composited by default.
KDE teams made some smart decisions, which are paying off still today. Back in old days the solution they found was to "make KDE themes aware of compositing. That is each theme contains an opaque element set which will be used when in non-composited mode."
The fact whether compositing is used, is globally available through a standardized X11 manager selection. So whenever the compositing state is changed Plasma is notified and switches the used elements. Simple and elegant.
He then pointed out that in KDE, "The compositor is a separate module inside the window manager which just gets started by the window manager on start-up. It lives more or less for itself and is just notified when a new window is added to the window manager and so on. Nothing inside the window manager really depends on the compositor. That means it would be more work to get KWin requiring compositing than to keep supporting the non-composited mode."
That's when he talks about gaming:
And having the non-composited mode around allows us to do things like turning compositing off when running games or heavy OpenGL based applications such as Blender. So if you want to get some of the now finally available games for Linux, KDE Plasma should be your primary choice to enjoy the game. I have also heard of users switching to KDE Plasma because we still provide non OpenGL based setups.
So, if you are playing games under Linux, better switch to KDE.