While mining, I experienced some extreme lag. This has made the game unplayable. When I mine blocks, they simply disappear like it is creative mode, but I'm in survival. I eventually tried to walk away with the fps varying from 0 to 15 and eventually I was teleported to where I last mined some blocks where they had reappeared. I had no other programs running, and I have closed down Minecraft and the problem was still in effect.