Did that. Same result. X plane 11 ran great for me before pb 14.
Okay, update! I was reading some posts over at the X-Plane.ORG forums and found some references to deleting the preferences folder. I went ahead and backed it up, deleted it and restarted X-Plane 11 PB 15, problem solved. Runs great, framerates are in the lower to mid 30's.