first, let me tell you that Forge saved my day. I want a server with a huge economy, more than 30 items and tons of stuff to explore. That is why I stopped using craftbukkit after 2 years and started using forge for some months now - which was the best idea ever! This project is awesome.
Since the last 3-4 forge updates I made, however, I have a huge lag problem. Mobs do not move or only move like if I have 4 fps or so. If I mine, the block's drops are dropped with a delay. And if I try to slay a mob, it seems I do not cause damage at all (also, no Matmos sword sounds) and then, like 10 seconds later, the mob dies and I hear a sound that sounds like if I hit the mob 10 times at once (again, Matmos sounds). In creative mode, I place 10 blocks and no block place sound comes, then after a moment, 10 blockplace sounds come at once...
I have a test server that allows me to re-create the issue anytime with more than 2 or 3 players online running in different directions. It seems that it has to do with exploring new chunks (sometimes new chunks are not even being created like in the pic another bug reporter posted earlier: http://i532.photobucket.com/albums/ee321/rdney29/Rodney/2012-10-03_100837.png). If all the players stay in already explored chunks - no problem. as soon as we head to new land, thats it....
I tested it with the following options:
1) Latest forge (Build 184.108.40.2061) with no mods at all @ i7-2600 Quad-Core and 4GB ram test server.
2) The forge that is runnig on the server right now + 50 mods: Build 220.127.116.117 @ i7-2600 Quad-Core and 16GB ram server.
I don't know what to do, I'm runnig out of options. Since this seems not to be a mod issue (I renamed the mods dir to modsXX ans also removed the coremods), I can do nothing to make the server run smooth again. I could whitelist anybody who wants to see the problem as it happens, sorry but I can not make videos or something, thats out of the range of my abilities ^^... (trying to be funny)
I am relatively new to forge, but before, I managed a craftbukkit server for 2 years so I guess I can say that I know something about servers... So if you respond to this message, feel free to give detailled instruction how to fix... It is sad to see players leave because of lags, so I hope someone can help. Tell me if you need further info.