...
here you can choose between auto, where the program decides how many threads are best suited for your system, and manual, where you can decide by yourself how many threads should be used
it is recommended to choose the auto option for best performance
if you want to define the threads yourself please note the following advices:
2-8 have good performance values (depending on your hardware setup and the optimization model)
Please make sure that at least 1 or 2 cores are left unused for the operating system!
...