Neither will be suitable for many games in Dolphin. Dolphin needs a very strong CPU, and all of the CPUs in the MS Surface Pro are Ultra Low Voltage (MS uses either -U or -Y based Intel CPUs to my knowledge). These CPUs are designed to use less voltage (to reduce the generation of heat) which in turn makes them lower powered than other non-ULV CPUs. You'll also rarely hit the maximum specified Turbo Boost while playing Dolphin since the CPU will almost always throttle down in an attempt to keep temperatures from reaching certain limits (which makes sense given the form-factor).
For laptops, you'll ideally want something like the i7-4800MQ or the i5-4200M (not the i5-4200U!). Depending on the games you want to play (please specify which you'd like to play, all games don't have the same HW requirements) it may be possible to go for something else as well.
For laptops, you'll ideally want something like the i7-4800MQ or the i5-4200M (not the i5-4200U!). Depending on the games you want to play (please specify which you'd like to play, all games don't have the same HW requirements) it may be possible to go for something else as well.