Hi, Drools
Your Max feed rate is set in Motor Tuning "Velocity" setting, It's used with G00 moves, The "F" value in your G code set's the feed-rate and remains constant for all other move's untill it's value is changed.
So it sounds as though your Velocity value need's to be reduced, Use g00 moves to set it Up.
Also in Motor Tuning "Acceleration",{Deceleration} play's a factor, Think of it as the speed your stepper's can start from a stopped condition and reach the max Velocity or decelerate from Max Vel., Without loosing step's.
In Config, General Configuration you can set a default F speed for Start up.
Chip