Is this a new change since you got the new computer? Was the same plane, same settings, same weather (everything), running at a higher FPS on the old computer?
From the log file it looked like you were using the Ramzzess 777. This is a very complex 3rd party aircraft. Switching to 3D cockpit view can drop FPS in any plane because a lot more detail, shadow, etc has to be drawn. (I lose about 10 FPS switching to 3D cockpit in the default Cessna.) You can try a lower rendering preset and see if it works better. You will need to restart X-Plane to see the changes.