A lift arm control system can be configured to raise or lower a lift arm assembly of an agricultural machine with variable speed so that the lift arm assembly can optimally perform under varying conditions, including changing a tool connected to the lift arm assembly while stationary and/or moving the lift arm assembly while operating at various speeds in the field. The lift arm assembly can be manually configured to adjust with speeds that are proportional to a user input. The lift arm assembly can also be automatically configured to adjust with speeds that are proportional to sensor(s) input of the machine, such as a vehicle speed sensor.