[Zope] strange performance problem

This has the characteristics of a network problem, but it may be somewhere else. Users report that the system just seems to stop responding for a few seconds, then recovers. Of course, I've not been able to reproduce the problem nor isolate a command sequence that triggers it, but I am convinced that it's real. This, BTW, happens on a lightly loaded machine with no apparent resource problems. Any thoughts, pointers, or techniques to isolate the problem would be appreciated. Oh, yes, the environment.. Dual Athlon Barton Stepping CPUs AMD2600, Tyan Tiger Motherboard, 4GB memory, 4x120 3Ware RAID 10, ethernet feed. RH7.3 OS, Python 2.3.1, Zope 2.6.2b3. Any help appreciate. -dra