I checked and tv refresh rate is 60hz 1080p. Planning to buy a rx580... Will there be differences?
Well, it looks like PS4 runs AC in 60fps, and a 60hz tv can have a maximum of 60fps. But, on PS4 I doubt you're running 60fps all the time, there's probably frame drops around buildings or when there's large grids of cars. You shouldn't have any of that on PC, you'll probably be a solid 60fps at all times (on a single monitor) so everything will look and feel smoother and you'll probably get less/no screen tearing which will also improve things. So, if you just looked at the label you'd seey they're both 60fps but I'd guess running AC in 60fps from a PC would be and improvement in the experience just from everything being smooth, stable, and consistent. Not to mention all the graphics and weather mods available on PC that can improve your image quality and introduce things like night and working headlights, those would be a mega improvement over playing on console. Of course you could also add two more TVs for the wide view, or get that nerd-helmet that straps to your face and transports you inside the game (<--my preference).
Not to mention that on console you're restricted to a very tiny sandbox, there's some flexibility in that sandbox but it's not large. The AC sandbox on PC is mahoosive, there's a mod of just about every track you can think of or full of awesome city roads for cruising, there's rally stages, special stages, hillclimbs, drift tracks, touge tracks, there's even some oval tracks now. For cars you get vintage cars, modern cars, street cars, rally cars, just about any version of Le Mans/F1 cars you could want, Transit vans, people carriers with F1 engines, a giant tennis ball with a F1 engine, an airplane, a hot air balloon, a racing lawnmower, Reliant Robins that tip over when you turn too fast, it's almost an endless sandbox of petrolhead goodness and for the most part the only limit to your fun is your own imagination because if you can imagine it you can probably do it in AC on PC. Ok, that might be a slight exaggeration but not much.
So, yeah, the overall differences are so big between PC and console that you likely wouldn't even recognize the PC version and you could probably play for years without ever touching the stock content if you wanted to. AC isn't perfect but it's come a long way and chances are it can scratch whatever driving/motorsports itch you may have.