I assume you're referring to the Engine settings regarding memory usage and processing cores. The general recommendation for those settings is half of the available machine resources. Remember that these are default settings and the engine will vary it's resource utilization as necessary.
Here's some documentation on Memory usage:
https://help.alteryx.com/9.5/Memory_Utilization.htm
When the machine is configured as a Server worker, consider lowering the default settings to ensure multiple jobs are handled as efficiently as possible.