I experience much worse stutters in planes with G1000/3000, less problems with CJ4 and steam gauge GAs pa28.
Wonder whether these airspace issues are exacerbated by airspace data also being depicted on the GPS unit screens? They presumably use the same data as the scenery, so that may explain why planes using these GPS units seem so much worse affected by stutters whereas simpler depictions of flight plans and waypoints aren’t maybe so badly affected…
Just a thought.