snapshots leave me with 1-2 fps

What I expected to happen was...:
to test out the new snapshot 15w44b

What actually happened was...:
i couldn't because of the amount of extreme lag that gave me 1-2fps and chunks not loading properly but when i paused the game the chunks loaded and i got an playable fps of around 40. then i unpaused and i get 1-2fps again.

Steps to Reproduce:
1.just load up the the game