The i3-4150 has a higher base clock speed (3.5 Ghz) vs the i5 4430 (3.0 Ghz), and will play more games at full-speed than the i5 since Dolphin is a dual-core program. The i3 will suffice for most of the games in Dolphin.
However, if you want the best experience, get an overclockable Haswell i5, either the -4670k or the upcoming -4690k. The i5-4690K is an upcoming refresh that has way better overclocking headroom, so it will give better performance. Pair that with a Z97 motherboard, and you'll be set.
Twilight Princess will hit major lag in every CPU once you get to a certain part of the game (Hyrule field).
However, if you want the best experience, get an overclockable Haswell i5, either the -4670k or the upcoming -4690k. The i5-4690K is an upcoming refresh that has way better overclocking headroom, so it will give better performance. Pair that with a Z97 motherboard, and you'll be set.
Twilight Princess will hit major lag in every CPU once you get to a certain part of the game (Hyrule field).