Yep same here, multiplayer is almost impossible, RAM usage is slowly rising up to 9500Mb, it's take only about 10mn to crash my game with a few players and nothing else. Also notice something else, if i start a mission (Tf51 cold start for example), RAM usage is about 3400Mb. Leave mission, restart the same, RAM is about 4200Mb, and it never stop....
Spec: I5 4670k, GTX 970Gb, 8Gb RAM, Windows 10 64 bits.