Hope this helps, Rob
1) Do you see the airplane begin to wander in 8x+ time compression if you use PMDG's Auto-Time-Compression feature?
2) Do you see the airplane begin to wander in 8x+ time compression if you manually set the time compression using the FSX menu or key commands?
Yes - using key commands. Have not tried menu
3) Do you have FSUIPC installed?
4) Have you tried deleting your FSX.CFG file and letting it rebuild?
Yes - problem still exists
5) Do you have Lockheed Martin Prepar3d installed on this machine?
6) When the airplane begins to wander, watch the HEADING ROSE on the NAV DISPLAY very carefully. Is it rotating in the proper direction and remaining in sync with the airplane heading? If not- we need to know.
Heading rose is not in sync and may move in opposite direction. For example, aircraft banks left but heading remains still and sometimes turns right.