KB

VMware Workstation

Host Power Saving Causes Problems with Guest Timekeeping

See http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&externalId=1227

Need to specify max CPU speed in config.ini, in Vista see %ALLUSERSPROFILE%\VMware\Workstation, if the file doesn't exist create it (this is all in the KB article).