If your 10.7.3's kernel starts using copious amounts of CPU and your /var/log/system.log is filled with getpwuid errors, such as:
Apr 5 07:39:56 cristi coreservicesd[29]: _scserver_ServerCheckin: client uid validation failure; getpwuid(501) == NULL
you may want to check out Ralf Becker's post on the subject.