thanks as ever for your prompt reply...

it seems that returning the ati radeon hd5770 card and replacing it with something else would be a sensible option? unless there is an imminent danger of apple actually fixing this problem...

would you agree? and which graphics card would you choose? we don't want to spend £1000s (if we can avoid it) but we need this system to work and play hd video as it was designed.... we have the 32 later/16 mix catalyst running on a 64 bit 8 core macpro workstation...

at the moment we can play one layer of hd video without dropping frames...


if you need any more info please let me know..