slowdown editing large body

I've got a page with a body around 1700 lines (about 100k bytes of text in html source form).

When I edit this, ckedit gets slower and slower until its unusable, entering or deleting a blank line can take 5-10 seconds after awhile. if I save the page, close the browser tab, and resume editing, then its fine for awhile.

this is really painful. the editing I'm doing on this page consists entirely of selecting a line, making it Heading 4, deleting/adding blank lines, and indenting other paragraphs by one indent. all it takes is 5-6 of these before it starts to go slower.

I'm running Drupal 7.latest on a apache/linux/postgresql server, and using the Google Chrome browser(latest) on a 16gb ram quad core (i5-3570k) Win8 64bit client system

I believe I have ckeditor 3.6.3