Got slung on a quad by an orca today. But not just any Orca. It was owned by the one and only Bamf. Got a free gold bar for helping him test somthing. +1 to all the Admins!
I have 2 Radeon R9 290x crossfire. But I would have gotten a little better CPU. I still average about 40-50 frames on ultra though. But get occasional lag spikes.
But seriously, make sure you have a good CPU for sure. Arma is completely based on your CPU. Having a awesome graphics card, but shit CPU will make a Shit PC.