I genuinely believe it has to do with server tbh. MSFS is the only sim directly connected to servers at literally ALL TIMES. You can’t run this sim without having an internet connection. What makes me think this? I’ve used XP9-12 and p3d v3 and v4 aside from
The odd crash I did 12, 14, and 16+ hour flights and not a single time did I experience performance degradation. All of those outside of updates where basically offline sims unless you used vatsim it whatever. Again this is my theory on it but it’s about the only theory that makes sense at this point.