The following methods may increase the display speed. 
1. Reduce the number of objects. 
2. Configure the trigger actions and script settings per screen, not per project. 
3. Extend the monitoring cycle for trigger actions and scripts. 
 Alternatively, execute the operation only when necessary, such as on the rising edge of a flag or under similar conditions. 
4. Insert the COM instruction in the sequence program. 
5. For the RCPU, set the device/label access service processing setting again. 
6. For the QCPU/LCPU, change the service processing setting parameter in the PLC parameter/PLC system setting. 
7. For the QCPU/LCPU, increase the value of the special register "SD315 (Time reserved for communication processing)" of the QCPU/LCPU.

For details on "COM instruction", "SD315 (Time reserved for communication processing)", and "PLC parameter/PLC system setting", refer to the following manual for the PLC used. 
"User's Manual (Function Explanation, Program Fundamentals)"

For details on the device/label access service processing settings, refer to the following. 
MELSEC iQ-R CPU Module User's Manual (Application) (SH-081264ENG)