Chunks not loading in single player

[TruePikachu]

Every now and then, I have observed situations where a group of chunks, either X or Z aligned, don't load. This never happened for me in Vanilla, even when playing 1.4.7.

I am quite early in a game right now, and I have already observed the problem, just by roaming looking for materials and a site.

This has been through the Single Player mode. System itself is 2x2.7GHz and 6GB Win7, launcher has configured 3GB and increased permgen.

Potentially related, but I have been having problems with audiodg eating at my CPU, but I'm not sure how related it is, since in theory, the chunks would load when audiodg "idles" again, especially if I am standing right next to said chunks. http://www.computerhope.com/forum/index.php/topic,138528.0.html is the proper location to respond with regards to audiodg.

EDIT: A bit later in the game, established a base, problems cropped up near home.

This capture is from one end of the rift

The minimap indicates the size of the "rift". I had been hanging around "Base", the green waypoint.

[TruePikachu]

Bump since I still have the problem

[TruePikachu]

Another day, another bump

[TruePikachu]

It is interesting seeing the single-layer thick bedrock at the bottom of a massive quarry I dug. Also still getting the problem, so bump.