factors influencing max feedrate

Hi,

After rectifying the problem with the "rough motor" I started testing
the motor on the bench with camtronics set for 1A 18V. The max
feedrate I obtained were:

Master5: 16 ipm
DeskNC : 12 ipm
TurboCNC: 12 ipm
(DOS Window)

Rebooting to DOS from A: drive

DeskNC: 22 ipm
TurboCNC: 15 ipm

What causes the feedrate to be different? It will be nice to
understand the factors so we can manipulate, etc.

Thanks

keongsan