Labels

Rain sound causes stuttering

Chest lag making the game almost impossible to play.

Lag on some superflat maps

The Nether still lags quite a bit

Mobs lag and go through blocks.

Tick times over 15,000 milliseconds per tick.

Extreme Performance Issues

Sound Artefacts When Lagging

1.4.2 Sound Lag from Running Water in Single Player Creative

Unexplained Lag with Debug Profiling

An issue with lan hosted servers

Consistent Lag issues on MP server without the same lag issues

Mushrooms spawn on the top of the Nether

lags when flipping a trapdoor

Lag When Downloading Nether/End

About Brightness

Lag in chunks with leaves - root.gameRenderer.level.updateChunks

Lagspikes and Crashes; Random

Really Laggy/Slow / FPS drop after updating to 1.4.4 / 1.4.5

Lag Spikes on computers with good specs.

Lagging between Chunks after rain

Block placement sounds are generated server-side, causing confusing sound delays if the user has a laggy connection

Reflecting Ghast Fireballs is nearly impossible

Gravel "flickering" and slight lag when destroying

Dark Leaves

Nether: serious lag, under attack before the world has loaded, then a crash

Sound jumps to consume large portion of CPU resulting in major periodic FPS drops (severe)

Game freezes for few seconds every so often

MacBook Pro Graphics Update 2.0 Major Issues

Block entities delay transition