My DH shared server Drupal performance has, over many months, gone from OK to poor to abysmal to, lately, whatever is below abysmal. For the past few days, attempts to do any sort of configuration have been successful about 1 time in 20 (the rest: Internal Server 500 errors or Page Not Found errors); right now, all sites are down completely, with Internal Server errors.
Troubleshooting has included Fast CGI <-> CGI, Drupal updates, cache cleaning, custom php.ini, much more. I spend far more time trying to get Drupal to work on DH than I do actually working on sites.
Support responses are fast but not helpful. It's sad because things used to work all right (within reasonable expectations for shared servers), my sites are extremely low on traffic or other demands, and I really like the DH range of features and controls. The problem is that DH simply no longer works for me.
Sorry, I have no answers here, just wanted to blow off a little steam before I start my shopping for a new host. : (