Typing lag in Lyx 1.6.4.1, OS X 10.6.0

[Josh Whitney]

I'm currently working on an early 2008 Macbook with 4 gb of RAM.  I am  
running OS X 10.6.0 and Lyx 1.6.4.1.  I've been writing some very long  
documents in Lyx and once they are more than a few pages long typing  
becomes excruciatingly slow.  That is, I type and the characters  
appearing on the screen lag the keystrokes by several seconds.  I was  
also having the same issue both with earlier versions of Lyx and with  
OS X 10.5.*, though it seemed a bit more mild with Leopard.

I do not have the view source window open.  I started typing the  
document with  instant preview off for math but after reading some of  
the questions on the mailing list I've turned instant preview on.  The  
typing remains very slow and also the preview for math doesn't seem to  
want to work (i.e., all math remains text instead of previewed as  
typeset).

I've read through the mailing list to see if I could find a solution  
to this problem but nothing seemed to work.  Any help would be greatly  
appreciated.

Thanks,
Josh Whitney