Until recently, we had at work a small cluster of about 20 small Windows servers (which have now all been virtualized). They were all configured to synchronize with the local time server. It was on an 1Gb sub-network in our own DC. I never got them to be less than about 100ms away from each other, which I consider to be an incredibly big difference.

Is that a normal value? What is a realistic expectation of time difference between machines running on a 1Gb network, and all connected to the same time server, and updating frequently, say every 5 minutes?

I would like to know this as setting timeouts and other parameters in a distributed application requires to take that difference into consideration.