drag1c,
CS servers does not control such low-level things. This is handled by the task scheduler of operation system, which is decides which processes and threads should run on which CPU cores and in what order. The task scheduler uses various algorithms and criteria to make these decisions, such as process priority, resource availability, hardware compatibility, etc.
For example, if you run two CS servers on your machine, one with 32/32 players and one with 12/12 players, the task scheduler will not split the CPU power equally between them, but dynamically allocate it according to their current load and needs. This means that if one server requires more resources than the other, the task scheduler may assign it more CPU cores or increase its priority. However, this does not mean that the other server will suffer from resource shortage or slowdown. The task scheduler constantly adjusts the resource allocation as needed to ensure fair and efficient use of the CPU.