I believe the best option for XMR on a hash/watt basis is still the NVidia GTX 750 ti - for some reason they hit a real sweet spot.

 There are some CPUs that can argue the point, though, but for some reason I don't think they've been beat (though they HAVE been challenged) on a hash/watt basis by newer GPUs.


 250 hash (common with a very mild overclock) on something like 45-50 watts actual usage (don't go by TDP, go by at-the-wall measurements)....