CPU Utilization During HD Playback: Blue-ray/HD DVD
ATI Radeon graphics processors traditionally demonstrate lower CPU utilization than Nvidia GeForce solutions even when picture-in-picture mode is on. It results from hardware support of bit-stream processing for VC-1 codec implemented in all ATI Radeon HD 2000/3000/4000 solutions. New ATI Radeon HD 4770 performs very well, as has been expected; however, there is no breakthrough here: it performs just like its predecessors. Besides, RV740 chip utilizes the CPU much more than ATI Radeon HD 4650/4670.
As opposed to VC-1, there are no winners or losers with MPEG4 AVC/H.264: the average CPU load varies from 20-25%, which is low. The ATI Radeon HD 4770 is good in this test, but its CPU load is higher than that of the ATI Radeon HD 4650/4670. We guess it is due to its new driver not being quite polished off yet.
MPEG2 has been very long on the market, and there is an integrated MPEG2 decoder in each modern GPU, so it is quite a surprise to see such a high CPU load in the Alien versus Predator movie. Perhaps this is a driver’s fault or the developer’s neglect of this codec.
The ATI Radeon HD 4770 has satisfactory results, being just as good as the other cards. Considering that the CPU load grows up to 40% at some moments, you should not save on the CPU for your HTPC if you’ve got a 4770 as your graphics card.