Hi there,    Whilst flying, I was getting the occasional lag spike and slight wobble in flight.    However whilst running Arma3sync, 'check for addons' service (software for checking and updating addons for Arma) I get FPS drops down to 1-2fps. This then causes the aircraft to become unstable and climb, dive and/or bank.   Answer is simple, don't run that software, but I presume other software will cause the same type of fps drops.