notice that u used i7 as a better cpu just because it's newer which is completely wrong i7 is better in some areas but the cell outperform i7 in other areas including physics
GPUs are know from being able to handle physics better than the CPUs it was proven that PhysX apps ran around three times faster on the GPU in comparison to the CPU, although the exact amount varied depending on the game being tested – some cases were up to four times faster.
yeah that's why the cell processor is unique and powerful in handling physics, so they accomplished that realism using that wonderful chip don't make it sound like they built an engine for a typical cpu.
you sir are wrong and i quote from an article;The STI Cell Processor found in the PlayStation 3 operates in a manner similar to the Ageia PhysX hardware; its design was driven by similar considerations. Unlike ATI/NVidia's GPGPU solutions, and like the PhysX, this design is more about providing each parallel thread with a large working set and more of the inter-thread communication and control found in a general purpose processor. As such it is very well-suited to physics calculations