scook
Maybe this will help http://forum.cakewalk.com/FindPost/2731416

 
It did! Thanks again, Scook. It's weird that that has been a problem for years and can't be fixed other than using a workaround.
 
Equally weird, at that link I read this:
"So I pulled it back in to 75 and that's really close to what I need it to be."
So I set mine to 75 and it sounds like it's in the pocket now. I thought it would be a lot of trial and error.
 
I'm thinking that it must be related to the 96 kHz sample rate because I wasn't having the problem using 44.1/ 24.

96K is hard on the CPU and hard on I/O.

Fwiw for others reading this thread. The playback and record buffers are very much a system specific setting. For example my laptop runs much better at 256 than it does 512.  My main system is the other way round. Both have similar processors (i7) although  my main system is quicker.  Go figure...