Konakona
https://dolphin-emu.org/download/ is the official download link for dolphin. (always best to get it from there).
The latest development versions are not only the best in terms of emulation/accuracy and features, but its also the fastest versions of dolphin to date.
https://wiki.dolphin-emu.org/index.php?title=Main_Page you can look up specific game configurations aswell as compatibility and sometimes even performance/benchmarks of different spec pcs for it.
If you are getting lag in emulation, its because you dont have a powerful enough cpu to emulate it (emulating requires 2-100x the processing power per instruction of the original system).
Dolphin, and most any other emulator for any system can only use a max of 2 cores. (so more then 2 cores does pretty much nothing for performance in emulators).
As such, amd cpus are NOT recommended for emulating GC/Wii games, since they have relatively low IPC (instructions per clock) performance.
You want a 3rd or 4th generation intel cpu (4th gen haswell cpus are by far the best option).
Id suggest looking for something that is like 3.4ghz+ and using the haswell architecture. (some games may require 4.0ghz+ overclocked haswell cpus)
Nick
Dolphin is the best emulator but you have to fine tune ever setting to eliminate choppy audio and video lag.
Sometimes there are videos on YouTube of the best settings for certain games. For example, I found a video on YouTube of the best settings for Super Smash Brothers Melee with the Dolphin emulator. Haven't had any problems since.