I've been having a huge lag issue and discovered my server has a tendency to climb in ram usage, as pictured here. I've tested all mods individually on a copy of the server, with the world reset and at 1GB of ram for testing, and it happens regardless of the mod used. Here is a zip file of mods I'm using if you need it. I can provide any other info needed. I'm not doing anything special to recreate it but it does get worse when people connect to the server.