What about multicore CPU's here?
This may be a better question for the OS, not xymon. Xymon is only reporting what the server says for load/cpu usage (or for any other value for that matter). Based on your disk "C" reference, I am assuming you question pertains to windows. When I pull up the Task Manager on Windows, there is a "CPU Usage" monitor/graph/thingy that is reporting a single value regardless of the number of CPU's the machine has. It is my belief that this is the value being reported (although I am not involved in development of bbnt, etc.) For *nix, the "load" is not really a direct function of the number of cpu's, it is (if I recall correctly) a count of processes in the run queue. I don't know if "CPU Usage" under windows is the same thing or some type of aggregation/averaging, etc. Hope this helps.
later.
-- Mark L. Hinkle hinkman at hinkman.com