Does pfSense support SMP (multi-processor and/or core) systems
The standard pfSense kernels include SMP support.
On pfSense 2.1.x and before, pf(4) is single threaded so it is locked to only a single processor. Other processes such as daemons on the firewall, interrupt processing, and other system tasks will utilize multiple processors/cores.
On pfSense 2.2 and later, pf(4) is multi-threaded and can utilize multiple processors, as can the other system daemons, interrupt processing, and other tasks.