[cd34]

I am not sure it is the cable - while the signal is digital going from HD to the TV, I believe HD broadcasts are one-way and there is no signal handshake or two-way communication. What that means is, a low quality cable shouldn't slow down things -- a low quality cable would result in parts of the image missing.

If you look at the amount of data required for an SDTV signal, 480i, which sends 240 lines of data every other frame refresh. In order to do 480p, progressive, where every line of the broadcast is sent every refresh, it requires twice as much computing power. That's for a 4:3 broadcast -- I am not sure of the technical difference between PAL and NTSC, but, its a fairly close comparison. NTSC is 720 pixels wide by 480 pixels high.

When you move up to 1080i or 1080p, you are significantly increasing the number of pixels that need to be sent to 1920 pixels wide by 1080 pixels high. An HDTV broadcast is roughly 6 times as much data as the older SDTV.

So, I think the issue MIGHT be that the graphics processor is fine for handling older SDTV, but, in times of very high activity or a lot of graphic motion, you might be overtaxing the cpu.

Of course, I could be wrong.