Craig - I think you are on to something!!
 
Doktor - thanks for the suggestions - I did just find a new graphics card driver released this past week - but alas, it hasn't made any difference. As it seems to be mainly that one project I am having trouble with, I guess I can ultimately live with it. Not thrilled though!
 
Thanks for your help.

Just turn off the 64bit floating engine it doesn't work and causes tons of problems with the program not just vocal sync.  It's a compromise we shouldn't have to make but we do unfortunately despite all Cake's marketing claims