I'm using HDMU build 10847 and after watching a HD channel for about 7 - 8 mins I then find that the picture starts to judder or becomes distorted. For example, any movement on the screen seems to have a delay added, it is as if the picture goes out of sync with itself delaying some of the images - so watching a football match and a player then running across the pitch becomes impossible. If I change channel and then go back to the same channel it takes another 7 - 8 mins.

Anyone had the same any suggestions?

Additional information - The same thing happens on FreeSat HD channels, for which I don't need a sly card and as it takes 7 - 8 mins to start happening it cannot be my TV's refresh / frequency.