I own a 1640P and use P3.2 at the moment. The problem is that I ca't update to the latest P3.4 because of compability issues with mobo using NVidia chipset. :a
I have seen somewhere (can't remember or find where) that there is a T3.4 fw to address to compability issue.
A answer your question : use the latest availbable, ie the highest number. :iagree:
BTW : where did you find B3.5??? :eek: