QtC12->13 performance regression

Significant performance regression observed for QtC13 on Windows (QtC on Linux and macOS seem to be as fast). See 2 screen records (zipped) on firing up QtC12 and 13 - the freezing of QtC13 upon launching is obvious.

However, the reasons of such performance regression can be various. I've got 3 memory dumps and each of them shows different task at the time of QtC being busy. The first 2 are my local dumps and the third is from another reporter.
1. QtC is busy loading help files (which, by the way, may also explain calling out help files by pressing F1 is slow).
2. Android kit is being worked on.
3. CMake project manager is doing something - it is kind of weird since as far as I see CMake project manager should not come into play until one actually opens a project?

Deleting help files (.qch) and disabling Android kit do work for me - although I believe it should not be a valid solution. Plus, there are unexplainable reasons, e.g. CMake project manager. I don't know what can be done to address that. Something has to be done here to investigate the regression as a whole.