This is entirely dependent on the device that is being monitored. If this is an ESX server version previous to 3.5 then this is a known issue with the ESX server's SNMP information. If this is some other device, then we would need to know which device and which IOS version if applicable. The number of possibilities is too large for us to venture any more guesses.
Please let us know and we can help further.
It is not an ESX server.
Here are the details on the device from Orion:
Machine Type Windows 2000 Server
Description Hardware: x86 Family 15 Model 2 Stepping 9 AT/AT COMPATIBLE - Software: Windows 2000 Version 5.0 (Build 2195 Multiprocessor Free)
Operating System 5.0 (Build 2195 Multiprocessor Free)
Having this happen on a Windows server is new. We have a pretty simple way of calculating CPU for a windows machine. If you have any of the toolset tools, you could see the Host Resources MIB hrProcessorTable values for your server. You should see it return a table of values giving the instaneous CPU utilization for each of your processors.
OID = 126.96.36.199.188.8.131.52.3.
The value we report is the average of all the values returned.
So if you get back 23 and 31 for your dual-core, we should show 27% CPU utilization.
If you don't have the toolset, then call support and reference this Thwack thread.