This issue involves chunks not loading/taking extremely long to load. The problem started today (11/22/14). Chunks used to just take up to 10 seconds to load, but now I have noticed significant performance drops. Over time the load time turned to ~30 seconds, and now it rarely loads at all, if it does, it takes at least 2 minutes. I am in an empty world with the Void below me, no blocks except infinite air. I can move around, but there is no way to load the chunks. Also, when creating or loading worlds, after the "Creating chunks: xx%", it stops for at least 45 seconds and says "Did the system time change or is the server overloaded? Running xxxx ms behind." The "xxxx" value is always between 50000 and 120000 (the delay time in milliseconds). In world chunk generation failure, when it finally loads, it does not say that the server is overloaded. Finally, I cannot exit the game without opening Task Manager and terminating javaw.exe. The problem is that when "Save and Quit" is pressed, Minecraft freezes. Overall, this problem is very severe. It makes Minecraft unplayable. Finally, even a complete reboot of the computer fails to fix the problem. I hope you can fix this, please!
-DarkLord515