RH2015 - Loading and search optimization

Hi,

Environment: RH 2015 12.0.2.384, generating merged WebHelp - almost 40 RH projects in total and 7000 topics.

Issue: loading the TOC and searching are very slow, and I need to figure out how to optimize them. However, I don't quite understand how they work, so I am hoping that someone on the forums could give me some pointers.

Current situation:

I've been testing this for a few weeks - some results below.

First TOC load:

• Local machine:
  • IE 11 - 25 seconds
  • Chrome - 2 seconds
• Client-facing site:
  • IE - 20 seconds
  • Chrome - 10 seconds

First search:

• Local machine:
  • Both IE and Chrome - 2 seconds.
• Client-facing site:
  • Both IE and Chrome - 25 seconds.

In the search settings, I have enabled highlighting, showing context, hiding the rank column and showing the total number of search results. (No substring search.) Enabling the AND option by default didn't seem to change the speed. Because we include a PDF version of each online help module, I also tried to exclude the PDFs from search, but that didn't make a difference either.

(I also tried to generate the same content in HTML5 format, and the TOC did load faster, but the search takes 2x as long...)

Unfortunately our client-facing site is password-protected, so I can't provide the link.

Questions:

1. As far as I can tell, a bunch of JS files in the wh* folders are loaded for the TOC and the search - am I on the right track? Does anyone know exactly how these files are generated? I opened the Developer Console in Chrome while searching for a term and it looks like loading one JS takes a couple of milliseconds, but there are so many files that it adds up to almost half a minute.
2. If I were to decrease the number of RH modules (say, 20 instead of 40), would that make a difference, or would I basically have the same number of JS files in total, just placed in different folders?
3. If I were to decrease the number of topics, would that help?
4. Is there something I can do to make the content load faster on IE? There is a big difference compared to Chrome, and most of our clients use IE...

Thanks a lot in advance!