1.6.2 launcher and update run very slow vs 1.5.2

When I was running 1.5.2 my FPS was 40 to 50. When I updated to 1.6.2 I run at 5 to 15 FPS.
When I first start a single player game on 1.6.2 the FPS runs at ~40 and then drops as the world is loaded making the game unplayable.

I have adjusted the graphics to run on the lowest settings. I also allocated more ram to Java.

I have also searched minecraftforum.net and have found a discussion of other people having this same problem. Here is the address:
http://www.minecraftforum.net/topic/1874258-why-is-16-so-slow/

I have attached a crash report.

If there is any more info that I can provide please let me know.