I haven't monitored CPU load while playing Arma III but I did notice my 7970 was barely doing any work while playing that game. I'm assuming this is using the same engine. Either there's a CPU bottle necking issue (AMD Phenom II 975 X4 @ 4.1GHz), poor optimization or both. Either way my FPS was shit in Arma III and I'm expecting it to be just as bad here.