I know this thread is from 5 (five!) years ago but I was experiencing some aliasing issues in CS5.5 and I was able to overcome them by doing a “Save RAM Preview” in the composition menu.
I thought this might work because I didn’t see the aliasing effects until the mov was rendered and it worked. Not sure if it’s the best workaround but I was about out of ideas.
Just something to try if anyone comes across this thread and can’t figure out anything else.