[CentOS] Confirming Multi-Processor

I have a test bed server that's pretty old- PIII Dual 550. I've done yum
update kernel-smp and when I run cat/proc/cpuinfo it lists both processors-
is there anything I need to to to confirm that it's fully utilizing both
processors?

I ask this because under the old OS (Fedora Core 2) I always saw an error
message at boot that said something about operating in single-processor mode
because the firmware was pre-2001. I don't see this error in CentOS. The
last firmware available for this logic board (N440BX) is dated 1999.