Since the release of Mac OS X 10.6.8 last week, a number of Xserve users have reported in Apple's discussion forums (via MacNN) issues with a hardware monitoring daemon known as hwmond generating significant CPU loads of up to 95%



From MacRumors:

Member Arminhempel reports a CPU load up to 70 percent after every reboot on several Xserves he manages; Jean-Serge Remy has an Xserve Xeon showing an 84 percent hit, while InfraredAD is experiencing a 95 percent load on a 2008 quad-core Xserve, essentially wiping out an entire core. Both the combo and delta versions of the update have generated errors and, so far, the only reliable way to fix the issue is a downgrade to Mac OS X 10.6.7.

  Mac OS X Server 10.6.8 Causing CPU Load Issues for Xserves