Even i am facing the same issue my Server CPU is on 100% after upgrade to SP2.
OrionAlertEngine.exe is reported to be the CPU eater. I even tried restarting the service but still its in the Process tree and eating up 70% of my server CPU.
Im having the same issue with a Quad core.
SP2 and avg 75% CPU utilization with the OrionAlertEngine.exe
Has anyone found a fix ?