I been dealing with this issue for sometime now. When i am im arma 3 and go to the multiplayer screen, the background animation stutters, along with any sound there, as well as if I am trying to type in a field it also delays. I have already reinstalled arma 3, updated my video card drivers and everything else I can think of and read of. I happened before the latest update, and still is continuing to happen.
I use to play on an old pc that was built in 2009, had purchased my amd radeon r9 270x which worked fine in my old machine. then i purchased a new pc, installed that same video card in this new pc. reinstalled arma 3 and that is when the problem started with arma 3. Been this way since before the last 2 updates, neither has fixed the issue.
this only happens in arma 3, arma 2 works fine, other games work fine. and only happens in the multiplayer screen, once i get into a game, i get 40-60fps.