On my (self-hosted) WordPress installation, loading the 'Add New Post' page takes under 1.5 seconds. When static files are cached, it takes well under a second.

On my (self-hosted) WordPress installation, loading the 'Add New Post' page takes under 1.5 seconds. When static files are cached, it takes well under a second. Something is clearly wrong with either your connection to the server, or their server configuration (the former seems more likely).