Very poor world generation and overall FPS

Fairly recently I've noticed incredibly poor performance both while generating new worlds and while playing ones already generated. I suspect there are some issues in the world generation being that it came into affect fairly recently in 1.7.0

I've used the awesome feature of the launcher to play older versions like 1.6 and I do not have the FPS issues experienced in 1.7.9

Blocks remain even after I destroy them, then after a couple seconds they finally disappear. Upon first generating, the world is non-existent (as if "falling out of the world") and i just fall, then suddenly it will appear and i hit the ground. In some instances I even get 0 FPS and the game freezes.

I know my computer can run the game with max settings because I've done it and gotten 150-200 FPS.

For video reference if you watch the beginning of my YouTube video you'll see the issues, along with my frustration. Here's a link:

https://www.youtube.com/watch?v=V0MaYrKR-nk&list=UUvHYMgbapS7i1o2gFBgYqpg