PC specs priority to improve emulation?

CPU. At the very minimum, a quad/hexa core from Haswell (4th gen) or up. But note that RPCS3 is probably the only emulator that multithreads this much. Other emulators tend to rely on single core performance mostly.
GPU either NVIDIA or AMD. No Intel, as their iGPUs and drivers are bad.
For RAM, 8GB or up.