M3 - rm5289, m5 - rm6489, m7 512gb - rm7110, m7 256gb -rm6342
M3 to m7 - rm1035, m5 to m7 - rm621
So it means m3 to m5 is only rm414.
M3 and m5 model price difference - rm1200
Rm1200 - rm414 = rm786 (256 extra ssd)
M7 512gb vs m7 256gb = rm768 extra (256 extra ssd) which it is very consistent to rm786 for m5 model.
so extra 256gb extra storage price is around there.
actually buying m5 model majority of price difference paid goes to the ssd.
Since m5 most price difference is for the ssd, the rm414 is actually very minimal comparing to the extra speed boost for turbo boost 2.7GHz vs 2.2GHz.
I had installed windows 10 on boot camp. I allocate 128gb to is x while the rest goes to bootcamp for my 512gb hardisk. I would say that for serious work user, 256gb can be very little in long run.
