CPU Load at HD Video Playback: Blu-ray/HD DVD
ATI’s Radeon HD processors traditionally have a lower CPU load when playing video encoded with the VC-1 codec. As you can see, the CPU load doesn’t grow up much even if we turn on the Picture-in-Picture mode on graphics cards that officially cannot accelerate two VC-1 streams simultaneously.
The Radeon HD 4550 has a very low CPU load in comparison with the other Radeons as well as Nvidia’s solutions.
Modern GPUs find it an easy job to decode MPEG4-AVC/H.264 streams. Few of them have an average CPU load of 25% even when decoding two streams simultaneously.
The Radeon HD 4550 offloads the CPU effectively when decoding video. Decoding a scene from The Day After Tomorrow with a bitrate of 40Mbps is not a problem for it.
We did not test the cards with MPEG2 video although some Blu-ray movies available on the market are encoded with MPEG2 HD. If you’ve got such discs, you may be interested to check out the CPU load when decoding a MPEG2 stream with a bitrate of 20-25Mbps (a free clip by NASA about launching a space shuttle).