It’s not new but Flightsim X is still a great ‘game’. If auto mode doesn’t suit the article has some recommendations for manual tuning.
When you play Microsoft Flight Simulator X, your game performance may be slower than expected.
Flight Simulator X automatically detects and sets the game to the performance options that suit your computer. If you manually change the settings to higher settings, you may experience game performance and display problems. To avoid such problems, avoid manually changing the settings. Let the game determine what settings to best fit your computer.