unplayable on low-specs pc / easily reproducible by limiting fps and render distance in options

I play MC on various low-end PC (1gig ram, first generation of Atom cpu with ntegrated 3d graphics) and I'm happy with the experience despite an obviously low fps rate.

I tried the last snapshot, thinking that the the chunk culling algorithm may improve the overall performance.

However, the game turns out to be unplayable.

• Every chunk takes a couple of seconds to load,
• Every single action on the MC word takes a couple of seconds to be synced with the server.
• A lot of lag spikes

The good new is that this regression in optimization is easily testable on a high-end computer. Just limit the fps rate at 10 in options screen. Also limit the render distance at minimum for more spectacular chunk loading lag.

Summary

What I expected to happen was...:

When I limit the frame rate to 10fps via the option screen in single player mode, my single player game should work at a low framerate but with everything else as reactive as possible: chunk loading, client/server synchronisation, etc.

What actually happened was...:

When I limit the frame rate to 10fps in single player mode, client/server communication messed up. Chunk loading lags. Chunck updates lags.

Steps to Reproduce:

1. Set the frame rate and the render distance to its minimum value

2. Play a single player game.

3. Notice that chunck loading and updating lags in much more proportion than the frame rate limitation.