My recommendations on the budget intel side (which will have vastly higher single threaded performance [better in Dolphin] but inferior multithreaded performance [general computing]) are the Pentium G3258 and the i3 4130. The Pentium has a solid single threaded performance which will certainly play Project M at full speed. read more
A comprehensive tutorial for running Project M on the Dolphin Wii Emulator on your computer! read more