Ok.... just a couple of questions more then I will let you live :)
Asp.Net has it's default output cache provider (you can set duration and parameters in page output tag) is it possible to activate that in the free dnn version? If not I guess is still possible to implement a custom cache provider for pages? I did a quick search but didn't find any "ready" output cache provider for DNN, it seems that it was built in in the free version prior to Evoq?
Any suggestion? This won't benefit logged users but for anonym users and heavy hitting pages like home page and such it would be a great performance boost of course.

About the modules.. What is the relation between the settings in Host > Advanced Settings > Performance, where you set memory/file based cache, heavy, and the "per-module" caching.
For example I set "file" in the advanced config. Then went to one of my modules in the home page and the default settings where "memory" and "0" duration. So what's the point of setting "file" in advanced host config? Also the "0" duration means until auto-expiry (memory full or app restart) or means "don't cache"?

Sorry for bugging

Ok now it's more clear... the misunderstanding was because a third party module didn't set the default configs set in host settings.
Duration of "0" in the per-module setting means "don't cache" or "cache until expiry"?

About page output cache, setting in IIS would be the best option BUT this won't serve up-to-date to authenticated users, this will always serve cached pages to anyone I guess.
So this anonymous/authenticated serving I guess is something is handled by DNN.
I tried adding the default Asp.Net Output Provider in the web.config but yet it won't show up in the dropdown for page output cache.
What I still didn't understand is if it's possible to add a custom provider to DNN free version or not since adding it to the web.config didn't do the trick and I didn't find any cache provider in the store