When you say 'Tablet' could you define that a bit better? To me a Windows Tablet is a Surface. I have a Surface RT but there is a Surface 'Pro' or something like that.
Generally speaking if you are speaking of a 'Surface' when you say Tablet the memory model that is referenced is storage not RAM. If you are speaking of a touch enabled notebook I'd go with as much memory as I could comfortably afford...but I would allocate the same rule to a rack mounted workstation also.
I also agree with mudgel that if you are thinking of running any version of X3 on tablet (see previous question) you will be disappointed. On the other hand I use my Surface RT has a control surface for X3 on my primary DAW. It's has a lot of utilitarian value.
Regards,