I'm not that smart so I go through tech books slowly so I can hopefully retain more of it and maybe even apply the knowledge day to day as I acquire it. I've always been jealous of people who rip through a dense (knowledge dense, not pages dense) tech book in a weekend and say they got it all.
The books that are more code oriented, I read on the computer so that I can type and run the code as I work through the book.
The books that are more theory or higher level I read on an e-reader.