Wafx

Hey, I've recently set up a tekkit server and everything worked fine, no lag or anything with only allocating 3gb of memory to the server and using my client of the same machine with 1gb memory. (Now, during the issues below, I've tried giving the server as much as 7GB or memory as well, further info below) However somewhere along the time where the login servers had issues we discovered issues on my server as well. At first I thought "oh well, it's probably due to the general server issues" and we kept getting java.socket errors while trying to login to the server. (This is me and 2 buddies) The server would register the login attempts and that people got disconnected so the server is reachable and everything. When we actually manage to log onto the server everything runs insanely slow, it's like negative FPS and after that it takes forever to even shut down the server. I did load up a new clean world this morning and that one worked out fine, and this leads me to the thought "Did someone place a bad block or something?" Is there anything that may cause severe lag that I should be aware of? I left the server up during the night for my buddies to play, this was the day before the login issues. I logged on the morning after and noticed they went nuts with quarries and stuff but everything seemed to work fine. I left the server running to let the quarries do their thing, and when I got home everything was pretty much broken. What makes no sense to me though is that during the time when I logged on in the morning to check what had been built during the night and to when I got home from work, nothing new was built, last block was placed at around 4 AM by them, I checked up on it at 7AM and then at 5PM again, nothing was built or placed between 4 AM and 5 PM, other than the quarries doing their stuff. Now, I'm still very new to minecraft servering, I've read something about a tool to remove stuff and it being impelemented into tekkit, could anyone point me in the right direction? Or if it's nothing that actually has to be removed, what could be causing this insane lagg? We're talking 1-3 minutes to log in and 5-10 seconds delay in movement due to graphics not even loading up thus making it feel like playing with negative-infinity FPS. Thank you for your time. B.R Wafx