The 6700XT should be fine and would have a lot of extra headroom for running at 4K with the most advanced shaders currently on the planet. You might also be able to get by with a 6600 but you may not have the extra headroom if you want to stream and stuff like that at 4K using the GPU at high bitrates at the same time. Iām not even sure if having a faster 6700XT would help in this regard because Iām not 100% sure how encoding works on AMD cards, but what I do know for certain is that the quality and encoding efficiency is currently worse than both Intel and nVIDIA and they have a lot of catching up to do.
If you go with an Intel non-F CPU, you can take advantage of the dedicated encoding block in the IGP to more or less negate this shortcoming. If you went with an nVIDIA GPU, you could easily use an AMD CPU and not have to worry about encoding performance.
Then again in general nVIDIA GPUs are more expensive for the rasterization performance they offer and they have higher driver overhead so AMD GPUs tend to perform relatively better than them when paired with older/slower CPUs.
So these are most of the pros and cons here. You donāt have to pay more for a 3060Ti in order to have the ultimate emulation experience, you can step down to a cheaper nVIDIA RTX 2060 12GB, 6GB, 1660 Super or Ti, RTX 3060 or RTX 3050 and be just fine.
As for the CPU, you donāt need much. If Intel donāt leave out the IGP because it can come in handy. Anything in the XX400 range from the last few generations should be fine. With AMD the X600 range would be excellent from the 3600 onwards.
So just consider all things once more and make an informed decision but donāt overspend unless you know youāre going to be doing other things with the system besides emulation.
You can take a look at my shader preset pack to see a good example of what can be achieved with the different performance tiers of probably the most advanced Shaders/Shader combinations in the world - HSM Mega Bezel Reflection Shader.
I donāt use generally use curvature but certain types of curvature need some serious GPU grunt if also using the highest Mega Bezel performance tiers but do note that the highest performance tiers are not a requirement since the lower ones can look very close in terms of the quality of the CRT effects.