Damn, I’m jealous. The nearest one from me is like an hour and a half drive one way.
Massive. I bought my brother a 5600X to replace his, uh… I can’t remember. It might’ve been older than a 3600, and it was leaps and bounds on him. For you to go to a 7800X3D would be gigantic, especially for modern WoW. I came from an i7-8700k, and was suffering as little as 24 FPS while recording Mythic Aberrus boss fights with my guild, and I was progressively getting more conservative with settings. (I also went from my 1070 Ti to a 6700 XT, and 2400 mhz to 6000 mhz RAM at CL30.)
I think I recorded Mythic Nymue with max settings at 80-115 FPS (though the full grass pre-pull still brings me down kinda hard). Back in Shadowlands I was getting maybe 40 FPS recording Mythic Sylvanas, and into SFO. Dragonflight really hurt performance for some reason, and something with a type of particle or voluminous effect related to it still hits hard.
Edit: The final boss recording I did on my old setup (but with a 6700 XT) was Mythic Council of Dreams, and I was around 45 FPS average, with some spikes up to 60-65, depending on where I look and what’s going on.
At this point, WoW would just need more optimization, or a (somehow) more powerful gaming CPU needs to come along. As far as the 7800X3D, it runs a lot cooler than Intel’s top CPUs. You could probably get by with a fan cooler if you can’t afford an AIO at the moment. Unlike Intel’s top CPUs, it doesn’t require a high end AIO to keep cool.