Massive lag spike and loss of sound after mission start

[makkaravuori]

After the last update, I have been getting this problem that shortly after mission start DCS turns into literal slide show and at the same time I lose all game sounds from my headset. Happens every time, only time it takes to do this is slightly varied each time. Sometimes the laggy slide show goes away, game runs quite smoothly but the sound doesn´t come back. Most often the lag keeps on going and I need to shut down DCS. 

This started after last patch, and updating to 2.9.6 or repairing the installation didn´t help. Any clues where to start looking for a fix?dcs.log.olddcs.log.old