There is a common issue on the community server of memory leaks, so we advise people to restart after the first mission. I tried to do it without to see if the new performance build fixed the issue, but it didn't. Since we are using many mods, it could be one of the mods causing the issue, but posting it here just in case it might be something related to vanilla arma 3.
related files: https://dl.dropboxusercontent.com/u/17881511/Arma%203%20Out%20of%20memory%2003-02-2017.zip