New in 6.4-4
For applications/renderers that do not support setting a specific number of threads, this section is not visible.
Slots = Threads
If this box is checked, it tells Qube and the application (eg, Maya) to use the specific number of threads listed in the "Specific Thread Count" field. If this is not checked, then the "Specific Thread Count" value is passed only to the application, but Qube is unaware of the number of cores/slots it should reserve. In most cases, you will want to check this box, unless you have Designer licenses, in which case you would only set the numeric value.
Specific Thread Count
This tells the renderer to use a specific number of threads for rendering. The default is one thread, which for any modern renderer will underperform, and when combined with the slots=threads, will swamp most workers by running as many instances as there are slots (eg, a 24 core machine would run 24 instances of the application/renderer). A better value is 8 (assuming you have 8 cores, as most modern machines do) which means that each instance of the job will use 8 threads to render, and, when combined with slots=threads, will reserve 8 slots while doing so.