I’m not sure about how to speed read technical books. When reading technical books I tend to use a highlighters and pens. I dog-ear (fold the corners) on pages that I know I will need to review. Then, on a second read (if necessary), I can look for the dog-eared corners, highlighted text, and my notes in the margins. I try to read quickly, but some types of information are too complex to understand without stopping to think about them.
I think that if speed reading technical books is possible, it depends on choosing a technical book on a topic that one is already familiar with at the level of that book.