The chip that put pixels on your screen in the PS2 had what is called crazy bandwidth to its target rendering memory. It was nothing like a modern GPU (Graphics Processing Unit), thus to do certain things, went over and over and over and over in many passes to get the desired result. The GPU in the PS3 is not capable of doing this. Modern GPUs work in a very different manner. Thus, what it means is that you can't get the GPU in the PS3 (RSX) simply to do the same thing as the GS (Graphics Synthesizer) did. On a PC this isn't such of a problem, modern PC GPUs have the capability (almost) to copy the GS and do it through brute force.
