bSmall
It depends on the route and scenario and baseline use by the OS. On my win 7 64-bit rig the OS baseline RAM is 2 - 2.5GB usage, TS2016 uses anywhere between 1.6 - 2.6 GB RAM (Max I've ever seen) on top of that. Usually once the route/scenario is loaded the RAM load stays fairly constant, and shouldn't change much at all.
These figures may depend on the usual hardware factors, mobo, cpu, OC, RAM speed and latency and so on.
8GB is usually plenty for TS 2016 but if you use SSDs it might be worth increasing the RAM to 16GB which should reduce the load on the SSD and help lengthen its life.
But TS2016 can access up to 4GB RAM if needed. (Plus more importantly - a maximum of 4GB of VAS running in a 64-bit OS)
IMO Stutters in TS may NOT be due to RAM, as its latency is measures in nanoseconds, and I've never see a nanosecond stutter.
These figures were measured dynamically using an appropriate Logitech Keyboard, G19 Pad or a Pertelian.
Regards
pH