So I am happy to report this has been resolved. Apparently this is a well documented issue discussed in the LM P3D forums. Its a native P3D issue and basically causes erratic and high CPU/GPU usage resulting in the stuttering. The fix? Right click the P3D desktop icon, click Compatibility, and check the box 'Disable fullscreen optimizations.' I conducted a test flight from Orbx's KSAN to FlightBeam's KSFO, flying over both TrueEarth Southern and Northern California. There was no noticeable stuttering like before...buttery smooth the whole way. There was some small stuttering approaching San Francisco, due to the scenery loading, however this is normal, nothing like before.