@montrealsoon, I remember that puzzling statement about the add-on stressing all 3 cores. It must have been due to bloated software:(
Edit: Apparently it used 4.7 million lines of code:
http://blogs.msdn.com/xboxteam/archive/2006/11/03/emergence-day.aspx
"The Xbox 360 HD DVD Player, for the most part, is an entirely software based implementation. Other players on the market have specialized chips (called DSPs) that decode things like H.264, MPEG, VC1, DTS, Dolby Digital, and other codecs. Much like how backwards compatibility for Xbox 1 works on Xbox 360, the heavy parts of HD DVD are all done on Xbox 360's triple-core CPU.
If DVD is an audio/video pipeline with some navigation data (go to the menu, start playing, etc.), HD DVD can be considered a runtime environment where audio/video playback is just one major feature. So let's break down that 4.7 million lines of code. I don't have the numbers for each component, but each of these is a very significant chunk: Video Codecs: H.264, MPEG-2, VC1, Audio Codecs: Dolby Digital+, DTS, TrueHD, LPCM, MPEG, HDi: The HD DVD runtime engine, GDI: Drawing stuff like menus, AACS: Cryptography/DRM stuff, MF: Audio/Video pipeline.
That's a lot of stuff. Some of the acronyms may not be recognizable. GDI is the Graphics Device Interface, which has been a mainstay of the Windows operating system for many years, providing facilities to draw stuff on screens. MF is Media Foundation - a framework for audio/video pipelines that was being built for Windows Vista. The Windows teams in charge of the above components all pitched in to make them work on Xbox 360 while continuing to work on other Windows projects (Vista, CE, etc.) - quite a task. "
