Hi Horst,
I already using ProCache with nginx, but only for static pages like blog posts and articles. I think PW altar database even if you are not log in. For example if page is not found.
The site is sport related with live stats. Initial data is loaded when the page is loaded. Then all changes on events are served via websocket in real time.
Thank you for your answer! I'm going to reorganize the site before it is too late.