Performance using the Visibility Property in the RTC compared to the Webclient

Hi everyone,

several weeks ago I started a question similar to this one, where I was asking how I could improve the loading speed of the Card-Page I'm currently working on.
The page is a mix of a person and a home page. Now I'm always setting some tabs in-/visible in dependance of the Record-Type.
I already tested quite a lot of things that were suggested and some on my own but without much success.

I also tested my Card-Page in the Web-Client now and the loading speed is much better.
My question now is, what does the Web-Client do, that the page loads so much faster than the same page in the RTC?

Another thing that I would like to know is what does the RTC-Pages consist of in the background? Is it C#-based?

Thank you in advance