Theoretically you can have 10 concurrent session of heavy 100Mbit going into a 1000Mbit. Only on a switch though.

The shared media segemtns would kill you if they were indeed shared.

The Collision Domain of the 1000Mbit Port would terribly Miniscule.

Since each Client (say 10 of them) could conceivably not have much collision domain either, especially wiith a store and forward switch with a good backplane.

I personally use a Switch with 200Mbit/port. 24 client ports, switch fabric needs to be 4.8Gbit. As long as you keep the ratio good, you'll see LOTSA goodness.

Right now, I am using these same ratios. I am getting .1-.3 milli-second response times. (100-300 microseconds) which is on a single segment of LAN (1 network).

If you have more than 1 Network, Uplink them with 1000Mbit... it does a network good. You could also use a router with 1000Mbit... but there I start doing 2000Mbit per port for switch fabric.

Reasons for this is called Non-Blocking networking. Nice theory to build a network by, doesn;t always hold true, but gives a very good infrastructure that should last a good number of years before the next upgrade/update.