From surfing the web it looks like VSMON.EXE consuming a high percentage of CPU for a period of time is a known behavior. I find it normally happens when I wake my system out of hibernation in the morning or have been away from it for several hours.
I do not doubt the value that VSMON.EXE provides but Zonealarm is the only security system I've used that impacts users response time as much as I experience.
Is there no configuration change that can be made so there are no prolonged peak (80-95%) CPU consumption.
I'm running Windows XP Home Edition SP3 on a Dell Dimension E521 ; 1.8Ghz AMD single core with 2.5GB of memory.