Frame rate drops significantly after 5-10 minutes into the flight. 47 frames to 10 ...!

Hi all,
I have a top spec PC and before the Sim 10 update all was fine and getting good frames.

After the update, the fame rate drops significantly after 5-10 minutes into the flight. i.e 47 frames to 10.

PMDG as well as default 787, is this a known issue?

Flight starts on the ground with 40+ frames soon after take off the frames start to decrease and then becomes unflyable .

Any suggestions.

As I say, every fine before the update, hi spec machine in use so I know its not the system as all was well before.

many thanks for your help in advance.

This will probably get moved to a different thread but you can try:

Switching to window mode and back to full screen
or
Turning off PG in the data menu run for about 5 min then switch it back on
or
Turn off live weather run for 5 min and turn it back on
or …

Make sure your card isnt running hot when you get to the point of the game slowing, if you check it leave the game running and use resource monitor or what ever program you use to determing system temps…