Q: Will UnrealEngine3 be taking advantage of PCI-E and use the GPU/VPU for physics calculations?

Tim Sweeney: All DirectX9 applications will automatically take advantage of PCI-Express as soon as it's available. We're using the GPU for visual effects processing, which includes both the obvious task of rendering visible pixels, and the invisible supporting work of, for example, generating shadow buffers and performing image convolution. However, given the limitations of the DirectX9 and HLSL programming model, I don't take seriously the idea of running non-visual processes like physics or sound on the GPU in the DirectX9 timeframe. For serious programming work, you need modern data structure features such as data pointers, linked lists, function pointers, random access memory reads and writes, and so on. GPU's will inevitably evolve to the point where you can simply compile C code to them. At that point a GPU would be suitable for any high-performance parallel computing task.