Seems to be quite common at a fair few locations, especially since Sim Update 3 (most recent update)
Try the same approach but with all online data services disabled. (Bing, photogrammetry etc)
Also, check same approach with windows resource monitor open, Flightsimulator selected (check box) and overview tab.
Keep an eye on “Disk” field. Do the stutters coincide with a sudden surge in activity?