I've been working a bit on optimizing a server that uses wordpress.  It has led me to some pretty startling memory discoveries. 

I did a test on memory usage in wp.  try this on a testing wordpress site if you can with cforms enabled  ( i had 5 forms setup on the server i did this on )

index.php, echo memory_get_usage()  before wordpress includes start.

then in a cforms init hook, print it again.  then throw a die() so you can see the numbers on page request.

you will be quite startled at how much memory wp is eating up.

For me, i was using wpmu, 4 subblogs, 1 main blog.  5 forms.  pre-wp php reported 50kb of memory being used for the script.   during init hook, it reported 10mb being used! 

This brings me to my suggestion.  I then did a die(print_r($GLOBALS))  i noticed that one big glaring problem is that all the cform data is stored in wp_options.   While cforms is not the only plugin that stores data in wp_options, the data cforms is storing in it can really add up.  especially when a few forms are setup. 

I really recommend making cforms store its data in its own table.  It would greatly decrease how much memory is needed when cforms is installed.   Those options can then be accessed only when a cform is inserted in a page instead of every wp page call. 

I know I'll be much more careful in what I put in wp_options in my plugins now.