IMHO most of the content in the books (especially non-fiction) is of no use to me. It's the 5% of insight that is added to my life that adds value and that I really want to think about.
Case in point, I'm trying to learn financial math. I get the concepts pretty well (just parabolic PDEs and similar things), but it would be helpful if I could more easily remember what the boundary conditions for "down and out barrier options" were or what the exact definition of "VaR" is.
Speed reading could help here, though I don't know how to do it.
Read a number of articles on the subject. Write out the definition in your own words or explain it to a friend. Complete a few textbook exercises to calculate the values you want to understand.
Taking the time to internalize a subject is significantly more helpful than quickly scanning words you do not yet understand.
A more traditional programming example is this; if you learn Java you need to understand, but learning the libraries is more a matter of remembering than understanding.
Some subjects are broad, not simply deep. Speed reading (or whatever) could help with the breadth.
The greatest value I gain from books is in identifying how the subject discussed can apply to my own circumstances. That insight often comes to me in the pauses between pages and paragraphs where I find myself thinking on what was just read.
I might be able to absorb a bit more information from speed-reading, but I don't think I could process and internalize the text nearly as well. Since that's why I'm reading the book in the first place, speed-reading seems of little benefit to me.