Free HD Content Playback
Notwithstanding its indisputable popularity, the DivX codec has never been a favorite of hardware developers. When it just appeared, DivX-encoded movies and clips would be slow on low-end PCs. Today, GPUs offer almost no support for DivX decoding, either. As a result, if you’ve got HD movies encoded with DivX, you have to buy a fast CPU to achieve good playback.
The Intel GMA 4500 ensures the lowest load of our dual-core CPU (46.9%) whereas the highest load (66.2%) can be observed with the Radeon HD 3870.
Considering the long life of MPEG2 format and the fact that a MPEG2 decoder is integrated into every modern GPU, there is no wonder that we have good results when playing MPEG2 clips and movies at 1920x1080. None of the tested GPUs required more than 20% of the CPU’s time when decoding the 1080i stream.
MPEG4 AVC/H.264 is popular not only among official content distributors but also among the distributors of HDTV rips of various sitcoms such as Lost or Prison Break. The consequence of this popularity is that the GPU developers implement hardware H.264 decoders into their products. As you can see, a typical 720p stream (1280x720) can be decoded on the GPU alone.
Our 720p clip encoded with VC-1 has a frame rate of 60fps, requiring a lot of resources to play.
As you can see, some GPUs, the Radeon HD 4670 and Radeon HD 3870, require more than 50% of the CPU time on average to decode this clip. That’s quite a lot. Most of the tested GPUs require about 40% of the CPU time, which is high, too.
The best result belongs to the Intel GMA 4500 core which needs only 34.1% of time of our dual-core processor whereas the Radeon HD 4670 and HD 3870 have the worst results (52.9% and 52%, respectively).
WMV HD is getting less popular due to its successor VC1, yet we tested this format, too. The graphics cards have about the same level of CPU load. The Radeon HD 4000 seem to be somewhat worse than the others, though.