The game, whenever I play in 1.8, will lag.

All that I expected was for the game to work like normal, but with a few less bugs and more blocks and features.
What happened was everything I expected, except for an uncontrollable lagging problem with the game. No matter what I did, the FPS would be either at 30, below it, or just a little bit above it.

All that needs to be done is to open the game (i haven't tried Superflat yet, so I don't know if that's affected), and attempt to play it. I have read a bit, and I'm not the only one with the problem.

Please help. I'd like to actually PLAY the new update, instead of just watching videos of it on YouTube.