There are many improvement options.

To improve startup time uninstall any modules from the Module Definitions that you don't need on the site.

Turn on Performance settings in the Host Settings/Advanced page. You can turn on Caching to help limit the requests to the database.

If all else fails, get a dedicated server/host, generally shared hosting environments (in my experience) aren't the best performing services.

While there are ways to improve DNN response, you may also need to look at your host environment.  I don't know EasyCGI, but many shared hosts have an operational threshold of number of sites per server that's based on a certain percentage being active at any one time.  Getting your host to move your site to a less busy server might help.  Switching to a host with lower loads may help.  Once you've tuned DNN, you might need to talk to your hosting service.

Jeff