FPS Drops from a solid 100 to about 60 in the latest snapshot

Certain snapshots seem to decrease in FPS. Below is details of what snapshots run at what FPS (Rough average while running).

14w02c - 110 FPS
14w03b - 90 FPS
14w04b - 80 FPS
14w05b - 75 FPS
14w06b - 70 FPS
14w07a - 65 FPS
14w08a - 65 FPS
14w10c - 70 FPS
14w11b - 60 FPS
14w17a - 60 FPS
14w18a - 60 FPS
14w18b - 60 FPS