Hi Missu,
You can check to see how many cores are being used by having a look by using the Developer Settings in Swarm Agent.
The processor count should be set to 1 or 2 less than the number of cores that you have available. This value does not change on the fly either.
When you’re looking at the Status windows where you can see the light build being processed you can visually see all the cores being used by going to the Settings page and in the AllowedRemoteAgentNames and set the name to be RENDER*
This will enable the individual cores being used to show their progress.
I hope this helps.
Tim