There are hardware changes that can be made to make a system run smoother:

If you are using a stepper system, check the amount of current being supplied to the drives modules inside the motor drive box (with the box powered off and unplugged). Turning down the current supplied to each drive could reduce machine vibration at resonant speeds.
A half stepping system can be replaced with a microstepping or a servo system, which can make finer machine movements, smoother motion, and a reduction in machining marks on a finished part.
There also software settings that can be changed to help give smoother machine motion:

If you see your machine ramping down between feedrate moves, you can increase the Continuous Contouring Feedrate Tolerance on the Configuration > Machine > Feedrate/Ramping Configuration Panel. For more information on the Continuous Contouring Feedrate Tolerance, please see the FlashCut CNC User’s Guide.
If you believe that the computer running your machine has poor graphics capabilities, you can increase your General and Jog Buffer times on the Configuration > System > Communications Configuration Panel to optimize machine performance For more information on the General and Jog Buffers, please see the FlashCut CNC User’s Guide.
If you see your machine stutter at higher speeds, you can increase the DRO and Viewport Display Update Periods (to 1.0 and 0.2 seconds, respectively) on the Configuration > System > Performance Configuration Panel. For more information on the DRO and Viewport Display Update Periods, please see the FlashCut CNC User’s Guide.
If you believe that your machine is cutting poorly during angled or contoured moves, you can increase the Timing Factor on the Configuration>>System>>Performance Configuration Panel. For more information on the Timing Factor, please see the FlashCut CNC User’s Guide.