This is just a very quite post - if you'd like to read it in length, you can hop over to my weblog to check out the full story.
If you are using TinyMCE, you might find that this is slowing down your ENTIRE site, depending on your settings for TinyMCE. In my particular example, this slowed down the site so much that I really got worried.
I already installed the TinyMCE compressor, which was a nice improvement, but it did not "bang" until i came across a very interesting setting in the compressor: enabling to hold the entire compressed TinyMCE in the local web browser's cache for a certain periode of time!
What happens is: the first time TinyMCE is needed, it loads over to your machine. AND it is planted right into the cache from where it will load every time again without the need to reload from your server. Enter a page with a TinyMCE enabled text area and instead of it seeing build up in front of you: puff there it is. Great experience.
Just go to the installed tiny_mce_gzip.php file and simply change this line:
$diskCache = false; // If you enable this option gzip files will be cached on disk.
to this:
$diskCache = true; // If you enable this option gzip files will be cached on disk.
and have fun! Certainly the experience will only live as long as the expiration of that cache item is not reached or until you empty your browser cache, but it is absolutely worth doing so.