hello,
I have the same problem with HD footage.
I get artefacts (yellow, grey, black) when I playback or render.
I rendered at 5 fps but the problem is still there.
My macpro is a 2,1 from 2007 and I can’t change now. (I can’t upgrade to 10.8.x)
Is there a solution ?
https://clair-obscur.be/pics/artefacts-1.png
https://clair-obscur.be/pics/artefacts-2.png