I have been banging my head against the preverbial brick wall ever since the SU5 update - crashes to desktop (CTD) led me to search for sim stability only for the situation to get worse. I did everything suggested bar make a burnt offereings! I renamed the community folder, I deleted content.xml, deleted rolling cache, deleted scenery.dat files, I re-enabled rolling cache, I added comunity folders one at a time, I uppgraded video drivers, monitor firmware.... nothing woked.
Finally I investigated the issue of screen sync. I tried G-sync on with V-sync (in game) off, HDR on, HDR off. G-sync full screen set, G-sync full screen & windowed set no luck. It wasn't until I disabled g-sync completely and re-enabled v-sync in game (with FPS at 60) did I finally get some stability. Praise the virtual sky gods!!! Ive just done 3 flights - YBAS area, Bora-Bora scenery tour and YSBK to YSSY in the default C172 without a single CTD.
So daring to hope I'm going to try renabling my community folder and see - wish me luck!