I'm not sure how noticeable it would be, frankly. The problem with benchmarks is that they often have little to do with how computers behave running the software you want to run. What they do is measure how they run the benchmark itself. Generally speaking, the Intel processors will be a little faster and more expensive at each processor type and speed.
I've been using Photoshop for 15 years and the computers of 15 years ago were pretty slow compared to those of today. Yes, Photoshop is more of a power hog these days but, truthfully, most any modern computer can handle it without difficulty. 3D gaming actually needs more computing power than Photoshop does so I wouldn't spend too much time worrying about that. If you have a modern, fast computer and a modern, fast graphics engine, you will be good to go with either brand of processor.