[tex4ht] speed of compiling to HMTL vs. PDF

[Nasser M. Abbasi]

Is there a rule of thumb one can use to compare how long a document
takes to compile to pdf vs. html?

I have a large document, 22,200 pages in PDF. Compiling it using
lualatex takes about 20-25 minutes.  Compiling using make4ht and
using mathjax mode, it takes over 6 hrs.

Is this something to be expected? about 12 times longer?

I would expect this to happen if I am using svg for images as
before, but since I am using mathjax, I thought things should
be faster.

The command I use to compile to HTML is (all on one line)

make4ht --shell-escape -ulm default -a debug
   -c nma_mathjax.cfg -e config.lua filename.tex
   "mathjax,htm,fn-in,4,notoc*,p-width,charset=utf-8" " -cunihtf -utf8"

So split level is 4 above.

The file is 80% math equations, and about 200-300 images.

Using TL 2021, and I run the above on Ubuntu under the updated
windows 10 Linux subsystem. I wonder if this has
something to do with it or is this just the way how tex4ht works?

The web page I am asking about above is  this one

https://www.12000.org/my_notes/solving_ODE/current_version/index.htm


Thanks
--Nasser