Lag Spikes, FPS unstable

In the lastest snapshots I've experienced significant lag spikes when moving around the world rendering new chunks. Fps becomes unstable and can plummet to 3/4 fps, and return to regular fps (60) on fast graphics/6-8 render distance. VBO doesn't seem to have an effect when on. Playing on a single player world generated in 14w29. Worlds generated in 14w30 have same issues. Playing with world border set to 300.