Yes, a Geoprocessing Server can take advantage of multiple processors. For example, when the Geoprocessing Server receives a process request, the operating system (OS) decides which processor to use for that request. Generally, the OS will give a new job to the processor that is being used the least. You cannot control which processor is used, and a single Geoprocessing task cannot be split up among processors.
Binding a process to a CPU is not recommended for the Geoprocessing Server.