My computer has always handled minecraft on highest settings, but now in this snapshot my I get about 30 frames and then it jumps back to 200 and then back down to 30

On lowest possible settings my computer jumps from 1200 frames down to 600 (That's way too many frames dropped)

Computer:
NVIDIA GeForce GTX 650
Intel core i7
3.40GHz
8 GB RAM
64- bit operating system
Window 8