Low Power Haswell for new PC

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Hi friends! I'm looking to build a new HTPC around Haswell. I'll be using it for DVR purposes, and so it will basically be on 24/7. I'm looking for the most power efficient processor that can also handle Dolphin duties for me. I'll be buying in the next few months and so I'm thinking Haswell. I'm looking to play in 1080 mode or at least 720, mostly the first party Nintendo games (mario galaxy 1, 2, zelda, super smash, mario kart). They seem to all run just fine on my Phenom II X4 965 based on my casual observation. I've been looking into the I5 3470S, 3470T series, hoping to save some power, but not sure if they'll(the Haswell equivalent) provide the juice I want. Any help is greatly appreciated!