Hold on, Don. A quick review.
Do you have the latest PT upgrade? You say PT works fine, but the same setup in RB (latest?) produces gradual latency.

Have you compared your PT setup with RB?
Have you checked the Windows Sounds and Audio devices? What is the Midi Playback setting and is "use default" checked?

Seems to me if PT (latest) works then so should RB. If you can say to tech support, that PT can do this but RB can't do it as well, this gives them a starting point.

I noticed that PT works smoother on similar functions than RB. Also Don I do not use synths so maybe I am out of my depth.
So try to compare RB and PT exactly - I think the problem is that comparison.

Good Luck - Ian


Ian
My "Original Tunes" Site
My gene pool needs more chlorine.