On my dual core laptop, many aspects of the game that are multi-threaded
froze and malfunctioned when I raised my graphical settings, my game was still rendering frames despite the issues.

When I boosted my render distance from 8 chunks to 32 chunks, I expected very short term framerate drop.

But, instead the mobs froze, physics failed, the chunk loading slowed down significantly, and textures were not loading on recently changed blocks.

1. Start single-player world
2. Spawn various mobs
3. Go to video settings
4. Boost render distance to max
5. Resume game
6. Notice how gravel and sand don't fall, mobs can't move(or move smoothly), TNT ignites but takes significant time to explode, chunks load significantly slower(or not at all), and newly placed blocks don't load their textures for a bit of time.

Watch screen recording: http://www.youtube.com/watch?v=gKRUAkBZX5A