NCE



V3.5 or newer NCE decoders with "Torque Compensation" are optimized as follows:  (Source Jim Scorse of NCE)

1) Make sure CV2 (Start Voltage) is set to 0
2) Set CV116 (Torque Kick Rate) to 2
3) The adjust CV117 (Torque Kick Strength) to get good slow speed (I start with 15 in CV117)
4) Try increasing CV116 by one or two to see if you can get better slow 
speed performance (you might have to bump CV117 up a couple of notches).

Notes:

I've found that in HO CV116 works best in the range of 2 to 4.
CV117 can range as high as 40-50 with old Athearn and Rivarossi locos
CV117 in my Kato locos is only set to 1