Discrete HTPC GPU Shootout

Before proceeding to the conclusions, let us deal with a couple of topics which didn't fit into any of the preceding sections.

First off, we have some power consumption numbers. In addition to idle power, we also measure the average power consumption of the testbed over a 15 minute interval when playing back a 1080p24 MKV file in MPC-HC.

There is not much to infer from the above power consumption numbers except that the GDDR5 based AMD 6450 needs to be avoided. All the cards idle around the same value. The AMD cards consume slightly more power when playing back the video.

I am sure many readers are also interested in the performance of the GPUs for 3D videos. With the latest PowerDVD and Total Media Theater builds, all the 3D Blu-rays we tried played back OK. Beyond this, we did't feel it necessary to devote time to develop a benchmarking methodology for 3D videos. There is no standardized way to store and transfer 3D videos. 3D Blu-ray ISOs are different from the 3D MKV standard, which, in turn are different from the standards adopted by some of the camcorder manufacturers. In our personal opinion, the 3D ecosystem for HTPCs is still in a mess. It is no secret that NVIDIA has invested heavily in the 3D ecosystem. In addition to the support for 3D movies, they also supply software to view stereoscopic photographs. If you plan on connecting your HTPC to a 3D TV and also plan to invest in 3D cameras or camcorders, the NVIDIA GPUs are a better choice (purely from a support viewpoint). If all you want to do is to play back your 3D Blu-rays any current GPU solution (Intel or AMD or NVIDIA) should be fine. Note that SBS/TAB (side-by-side/Top-and-Bottom) 3D streams (as used in TV broadcasts) are likely to have performance similar to that of the 2D 720p/1080i content.

From a broadcast perspective, MPEG-2 is a mature codec, but it is not very efficient at HD resolutions. H.264 is widely preferred. Current H.264 broadcast encoders take in the raw 4:2:2 10-bit data, but compress them using 8-bit 4:2:0 encoders. Recently, companies have put forward 10-bit 4:2:2 encoding [PDF] as a way to boost the efficiency of H.264 encoding. Unfortunately, none of the GPUs have support for decoding such streams (encoded with profile level High10). Considering that 10-bit 4:2:2 is finding acceptance within the professional community only now, we wouldn't fault the GPU vendors too much. However, x264 has started implementing 10-bit support now, making it possible for users to generate / back-up videos in the new profile. We would like GPU vendors to provide decode support for the High10 AVC profile as soon as possible in their mainstream consumer offerings.