That your PC can't handle
In case you were concerned that visually-stunning mech shooter Hawken would run well on your computer, you can always turn on the PhysX options that will ensure amazing visuals and mournful performance (for most).
In this video distributed by Nvidia, new particle effects, bullet turbulence, and floating embers are shown off. It's really impressive to see in action -- well, at least on Nvidia's computers, not mine. However, there is a copy-and-paste element to the particle effect that lacks the subtly I expect to come of next-gen.
All of this feels like a stop-gap until we get the processor-friendly physics promised in Unreal Engine 4 and CryENGINE 3, but Hawken's visuals are very impressive, nonetheless. PhysX is what made Arkham City a superior experience on PC (among other titles), so it's smart of the developer to lean on it, even if only a minority of high-end PC owners will benefit.
See how your PC handles the (Nvidia only) PhysX effects in Hawken beta. Let us know. I'm curious.