That's not really true. An A10 would give you more real threads so PS would perform better, in addition the integrated GPU would support OpenCL allowing you to accelerate a lot of your rendering processes using the integrated GPU.
Because PS is very good at paralleling a lot of image rendering tasks, you want an A10. An i3 is much better at single threaded tasks becasue each core in the dual core processor is faster, but with the A10 you will get more cores. Games don't usually take advantage of more than one core that well and that is why you find so many people reflexively recommending i3s. This is mainly a forum informing gamers of what hardware to pick after all. Additionally so due to the amount that actually having GPU acceleration would provide. This is all before overclocking. With overclocking, the i3 wouldn't even be in the same realm for only PS tasks.
The faster the better as far as an A10 is concerned, so I would be inclined to recommend a 7850k