The question, simply put, is the one in the title. Is it possible?
So far, my experience with scripting languages is that, to increase performance, you need to cache everything and later just serve the generated HTML files.
That's ok for some use cases, but when you really need to generate a new page in realtime, it's just impossible.
Drupal can take up to 3 seconds (or more!) to render some web pages (PHP execution time, not DB). That's crazy. Completely crazy.
If many projects (like Facebook) are using PHP, obviously the problem is mine. But googling for this problem shows that it's common. Too common.
(Of course I installed APC for PHP. It certainly helps, but PHP is still ultra-slow).
Must I assume this is the reality for Drupal / PHP?
Thanks.