Demystifying start render

[vvoyer]

Hello, I tried to read all content on start render and painting on IE.

It seems to be an awful subject as we only have small hints on when a webpage will have a good and early progressive rendering whether it will just show up the whole webpage after 3 seconds (bad).

I have a LOT of questions :
- What is triggering the first painting ?
- What do I need to do to leverage the start render ?
- Does some tags blocks the start render / progressive rendering ?
- Conditional comment ?
- Tables ?
- Iframes ?
- other ?
- Does some front end techniques are bad for progressive rendering ?
- More generally, what to do to ensure a good progressive rendering.

I know a lot of best practices for web performance but start render is a very difficult subject.