Some GC games are more intensive than any Wii games (for example the Rouge Squadron series of games from the GC are really intensive, but some WiiWare titles will run on a toaster), so its a misconception that Wii games are all inherently more intensive.
Phenoms are not great for emulation and they run really hot. It also won't handle Metroid Prime anywhere near fullspeed because it is also a CPU intensive game. Dolphin is a dual-core program, so the faster 2 cores are, the faster Dolphin will run.
If you want to go for a cheap but strong CPU, what I recommend is getting a Z97 board and the G3258. This will allow you to overclock to the same speeds as the i5-4690K/i7-4790K and have near similar performance.
If you can spend more money, get the i5-4790K with a Z97 board. That way you'll have the option to overclock in the future if Dolphin becomes more demanding. And you'll have a really good CU to play PC games with also.
Phenoms are not great for emulation and they run really hot. It also won't handle Metroid Prime anywhere near fullspeed because it is also a CPU intensive game. Dolphin is a dual-core program, so the faster 2 cores are, the faster Dolphin will run.
If you want to go for a cheap but strong CPU, what I recommend is getting a Z97 board and the G3258. This will allow you to overclock to the same speeds as the i5-4690K/i7-4790K and have near similar performance.
If you can spend more money, get the i5-4790K with a Z97 board. That way you'll have the option to overclock in the future if Dolphin becomes more demanding. And you'll have a really good CU to play PC games with also.