If you’re using a Lumia 950 or 950 XL with a relatively modern Snapdragon processor (namely, a Snapdragon 808 or beyond), then your hardware is fully capable of running a 64-bit operating system. That would pay dividends, potentially at least, regarding processing speed, security, and a host of other advantages. To date, though, Microsoft’s Windows 10 Mobile has been 32-bit, limiting the advantages that could be attained from 64-bit computing.
All of that is likely set to change at some point in the future. As we reported earlier this year, there have been hints that Microsoft would enable ARM64 support in Windows 10 Mobile. ARM64, just as it sounds, is the 64-bit architecture that ARM implemented in the Snapdragon 808, 810, and 820 (and will be the architecture used in their mainstream SoCs going forward).