We have adviced several procces get stucked and don't move along next step without any reason. Once BG services are restarted, PPM seem's to have common behaviour.
Currently, we have following stats at Process Engines, and we would know if its possible to improve process response times by increasing allocated memmory or adding more bg services.
In fact, we also would know the impact on performance of:
Thanks in advanced,
Thump rule you should never have more then 2 Process engine, we need to see if your process are getting stuck and that could be due to available memory and CPU too. Also you need to ensure to clean up the process instance regularly.