Symptoms

The CPU utilization has reached 100% on the machine with Processing Station.

Cause

All resources are busy.

Resolution

The number of processes used by the Processing Station can be reduced. For example, for an 8-core CPU the number of processes on the station can be set to use 6 cores only leaving 2 cores for the rest of the system.  It can be changed in the Processing Server Monitor > Stations > Station Properties by changing the Maximum number of processes: 
 

Additional information

Scaling
Estimating the number of CPU cores required by the Application Server
How to calculate the number of Processing Stations
How to tune up the performance of a Processing Station