And while 3D rendering capabilities used to be important solely for running 3D games, the mathematical powerhouses contained within a GPU are now used for lots of other tasks, such as high-definition video encoding and decoding, mathematical processing, the playback of DRM-protected content and those wobbly windows and drop shadows everyone seems to like on their desktops.
A better hardware specification not only means games run at a higher resolution, at a better quality and with a faster framerate - all of which adds to the enjoyment of playing a game - it now means you also get a better desktop experience.
Processing
Like CPUs, GPU development never seems to plateaux. Their power seems to double every 18 months, and this is both a good and a bad thing.
The good is that last year's models usually cost half as much as they did when they were released. The bad is that your card is almost always out of date, even when you do buy the most recent model. For those reasons, and because most Linux gamers won't want cutting-edge gaming technology when there are no cutting-edge titles to use it on (unless you dual-boot to Windows), we're going to focus our hardware on value, performance, hardware support and compatibility.
For value, we're going to look at models slightly off the cutting edge, including a couple of cheap options and a couple that are more expensive. For performance, we've run each device against version 3.0 of the Unigene benchmark. This is an arduous test of a GPU's 3D prowess, churning out millions of polygons complete with ambient occlusion, dynamic global illumination, volumetric cumulonimbus clouds and light scattering. It looks better than any Linux-native game, and it tests both for hardware capabilities and the quality of the drivers.
As the Unigene engine is used by several high-profile games, including Oil Rush, its results should give a good indication of how well a GPU might perform with any modern games that appear.
However, we also wanted to test our hardware on games you might want to play now. We tested the latest version of Alien Arena, for example, as well as commercial indie titles such as World of Goo. More importantly, we also tested the kit with some games from Steam running on Wine.
Steam is a games portal for Windows, and it has become the best way of buying and installing new games for that operating system. There's some very strong evidence that Steam will be coming to Linux before the end of 2012. If that happens, its Wine performance should give us some indication of how certain Steam titles will run on Linux.
Hardware
We tested five different components. The first two are integrated, which means they're part of the CPU package rather than being extra cards you slot into your motherboard. These CPU and graphics packages are often referred to as APUs - accelerated processing units.
We started with Intel's Sandy Bridge APU on the i5-2500K CPU, running at 3.30GHz, and because Intel takes Linux driver development seriously, we expected great results from a single package.
The other APU we tested has got a much better specification on paper; and that's the one that comes with AMD's A8-3850 APU package (aka AMD Fusion). This is the rumoured core of a PlayStation 4, and although the GPU on our model is likely to be less powerful than Sony's eventual successor, it will still be possible to combine its computational power with another external Radeon card using the hybrid CrossFire option enabled from the BIOS. It's listed as an AMD Radeon HD 6550D, and we used it with 512MB of assigned RAM.
