32bit NT4.0 Enterprise
4G Byte direct addressing and 16G Byte via PAE.
Even a 64G byte phone / PC / Tablet probably only needs 4G byte direct addressing. The rest can be "filesystem".
64 bit in some circumstances increases code size and no real increase in performance. Any performance increase is usually other changes not the increased addressing (which isn't physically much more than PAE can do on a 1998 32 bit PC).
Really twice the battery life would be better.
P.S. It's not about better Floating point but 64 bit Integers, which often means you can avoid slower less accurate Floating point. 80bit floating point has rounding errors, hence the "currency" type in VB which was really a 64 bit integer.