1) Do you see the airplane begin to wander in 8x+ time compression if you use PMDG's Auto-Time-Compression feature?
Yes 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 3) Do you have FSUIPC installed?
Yes 3a) Which version is installed?
4.934 3b) Have you tried deleting your FSUIPC config file and letting it rebuild?
No 4) Have you tried deleting your FSX.CFG file and letting it rebuild?
No 5) Do you have Lockheed Martin Prepar3d installed on this machine?
No 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.
When the airplane begins to wander the heading on the PFD and ND are not in sync with the bank angle. It seems to be too late, if you know what I mean.
If the aircraft finished its left turn and is starting to bank to the right, the heading is stille turning too the left and it takes some time before it starts to turn to the right.
Another thing I noticed is, that the standby compass is not in sync with the heading on the ND.
It seems to react quicker to the bank angles of the aircraft than the ND.
It also comes quicker to the correct heading as soon as I pause FSX.
When I pause, the sim stops and the aircraft stops too but the heading is still moving.
Sometimes it takes up to 10s to come to the correct value.
It seems the heading is lagging behind the rest of the sim.
I hope this will help.
BTW: I also have the issue with the pausing FSX (not the freezing aircraft).
Sometimes the sim freezes for 15min.
But the aircraft keeps to simulate, because when the sim returns to normal operatian, the aircraft has burnt fuel in the meantime without actually moving. ;-)