I was playing Minecraft 1.8.1 earlier today. Everything was fine. I just tried going onto the servers that i play on...and the server lag was unbearable. No one else had any. So i tried playing some SP...SERVER LAG! Everything in SP acted as if I were in SMP with terrible lag!
I had nothing but Minecraft running and I tried restarting Minecraft. Nothing! What the hell is going on? I have never experienced this problem before.