What sorts of latency values are currently reported in Sonar, and what is your driver mode?
Also, have you tried either increasing your Prepare Using XXXXX milliseconds time up from the new default of 250 -up to perhaps 500, 750, or 999, or adjusting the ASIO Buffer Size up to the next level - such as raising up from 64 to 128, or 128 to 256?
Bob Bone