Since I reinstalled my Windows I can't play multiplayer anymore. Everytime I play MP it takes between 5 and 60 min ArmA 3 will start lagging (Sound and Picture), also textures and models start glitching out. All I can do is wait and don't give the game any input and after a few minutes it either catches back up and does the same after a while or it will just crash without any error report and normally without stopping the ArmA3 task, which I have to terminate manually. Also the closed yellow desync chain will appear for a few seconds when the problem appears.
This will only happen in multiplayer and never happen in singleplayer or editor.
Edit: Since the latest DEV patch (from the 16.08.2013) this happens in singleplayer and editor too. {F21328} {F21329}