I'm using a Mac and PC, so that's not your problem. Hardware option? Faster and or more CPUs are it. Over 1GB RAM, I would stay away from virtual ram anything as you can introduce disk thrashing (bad) .

So is there anyway that you can skimp on AO? Will you be able to notice it in long shots after video compression is applied? Possibly not, at that's where shadow maps (very blurry) could help. Also items that aren't participating in raytrace calculations (which is usually almost everything not reflecting, refracting, AO-ing or GI-ing) should be disabled on a per-object basis. If tex resolution is not super important 

Everything is 3D is a hack or a cheat. If you know where to cut corners you can squeeze more CPU cycles but it requires a bit of forethought.