Also having these same issues since 1.26 update as well. I have tried DDU reinstall for NVidia drivers, Complete fresh install of DayZ via stream, and also removing any overclocking via GPU and still nothing has fixed the shuttering or fps loss/dips that have been really noticeable this update. I stopped messing with the hardware because i noticed with other games nothing in terms of performance has changed so it has to be something with this patch and optimizing. I have almost 6,000 hours in dayz and this is by far the worst performance I've had patch wise and hope that it gets fixed soon!