KB937882 - After you install SMS 2003 SP3, the Wmiprvse.exe process may generate high CPU usage on client computers during hardware-inventory operations

Don’t let this one bite your SMS installs – it is much like the SVCHOST.EXE problem, except it affects WMI.
I suspect if you install the WMI updates that were backported from Vista, it might help but that is unconfirmed so far.

Read about the problem and eventual hotfix here.