sp_sysmon gives more detailed information than sp_monitor. The “Kernel Utilization” section of the sp_sysmon report displays how busy the engine was during the sample run. The percentage in this output is based on the time that CPU was allocated to Adaptive Server; it is not a percentage of the total sample interval.
The “CPU Yields by engine” section displays information about how often the engine yielded to the operating - system during the interval.
See Chapter 39, “Monitoring Performance with sp_sysmon,” for more information about sp_sysmon.