James Dean

So my server is new and typically has 5-6 players on at a time. It is low pop, and plugin list is pretty small in my opinion. I've definitely played on servers with a lot more resource heavy plugins than mine. There are 71,486 entities currently with 4 players. They all are fairly close to the server location and have a low ping. They all experience rubber banding and lagging and looking at the graph on the control panel there are obvious big spikes in memory usage. I'm just confused as to what would be causing these big spikes and causing lag. Wondering if anyone else is experiencing this or knows what may be the cause.