For me as well when I enable auto time compression up to 4x it goes to that speed, but wings start rocking uncontrollably left and right to 30 ° of bank each side
And I use time compression up to 4x on PMDG 777, 737 and default 787
So I can't accept the answer "it depends to your PC performance", because I can understand a performance degradation, but not this abnormal banking.
I can't be in front of my PC for 6 hours or more, so without a time compression this aicraft is unusable for lonhaul flights.