AFAIK this will be dependant on a whole series of factors including your own PC setup, router, firewalls and AV, the cache being used and also the websites own setup as well.
Given the large number of possible permutations this involves solutions to any given problem will require knowing more detail about each of those individual aspects.
I'm sure, however, if you follow the link to RDHW's site you will find all the key info on exactly how all this works.
http://homepage.ntlworld.com/robin.d...ips/index.html