Minecraft - Major Lagg Spikes?

So whenever I play Minecraft I get these lagg spikes. In a bit more detail: I will be playing on a Minecraft server (IP: avic.us) and I will be pvping people. I will be getting 90 fps and 30 seconds later everything drops down and the fps is at 2. It is very annoying when trying to fight people in minecraft. I have tried doing everything: I set my java priority at high in the Task Manager, I re-installed minecraft, I out all my minecraft settings on low, and I even installed the latest Optifine for 1.7.2

So my question is how do I fix this? The lagg spikes are seemingly random and are quite annoying. If someone could tell me how to get rid of them I would love you forever.

P.S.: It is not the server… The server has good ping and all my friends don't get lagg…

Make sure you have VSync turned off. I was having very bad lag because of that. I would usually get around 120, then with that on, I'd get around 30.