Draw calls definitely aren't a problem on PC in this game, it tops 70fps even on a 3Ghz dual core:
Interesting. I'm not sure how to interpret from this graph that the CPUs are not draw call bound. It's not to say I don't believe you, I do know what you are saying but the min frames per second and the average frame per second are less than 10 fps apart. That means max frames are likely 20 frames more than the min frames, in theory. Overall this is really tight, all setups in that diagram the minimum frame rate is very close to the average frame rate. We'll need more data to know more - but without some sort of CPU and GPU utilization graph to go along with it, I'm not sure how to proceed.