I have two public servers with custom pack, and both have IC2Exp b821 (well, almost the latest version).
The servers are pretty crowded with people who build huge power factories with lots of stuff, some time ago it started lagging like hell, so I switched WarmRoast on and got pretty interesting results:
These stats for ic2.core.energy were taken for less than 10 people online, but they are actually a lot higher when there're 50 people online, and IC2's energy net remains the main consumer in WarmRoast.
First I suspected that this is because many players have solar panels from the IC2 ASP addon, or other power generators, which push the energy to consumers and lack it, so they are constantly regenerating the energy, while pushing it to the network.
But that was not the case.
Now the only problem I can think of why is IC2 eating so much resources from my servers is it's devices with speed upgrades, say a person has 12 recyclers with 20 speed upgrades each, no matter how many energy you have, they will tend to lag the server.
Please give some information on that. I know you're more into 1.8-1.9 versions right now, but if there's anything you could do to either optimize or fix in current IC2, I would be really greatful.