The first thing to do is to read this: http://www.vmware.com/pdf/vmware_timekeeping.pdf. It contains an explanation on how it all works and some troubleshooting hints.
In fact, the VMware Tools can only advance the clock, not slow it down. At VMworld 2007 VMware said that this will be possible in future versions.
The time can run faster if some kind of overcompensation happens. If your guest uses the PIT as its clock source it depends on interrupts to advance ist closk. But only the system which actually owns the CPU will receive this interrupts, so these are lost for all other systems. VMware keeps track of these lost interrupts and sens them to the guests which didn't see them in a compressed format. If the guest has its own compensation algorithm (because these lost interrupts occur on a physical system, too) it may lead to a clock which runs too fast, because the clock will be advanced by the later send lost interrupts and the compensation algorithm.
I'll never had that kind of problem with Windows, but very often with older Linux kernels.
The clock source the guest uses can change depending on what software you have installed. Some multimedia software for example changes the clock source.
In addition, running more than one time synchronization algorithm can also advance the clock too fast.
There might be more reasons than what I wrote here.
Some KB Articles about time running too fast in Windowes guests:
KB 1002742
KB 1227
KB 1005953
If you found this information useful, please consider awarding points for "Correct" or "Helpful" answers/replies. Thanks!!
vExpert 2009/10/11
[:o]===[o:] [: ]o=o[ :]
= Save forests! rent firewood! =
