It depends upon the material for me. Sometimes with technical or historical books that are essentially reciting data points then conclusions I can read much fas

It depends upon the material for me. Sometimes with technical or historical books that are essentially reciting data points then conclusions I can read much faster than 2x because if one is paying attention one kind of knows where the writer(s) are going - though I might repeat or pause to write notes or do online research sometimes to memorize and understand new terminology, but for fiction I have to be in a very specific mindset to imagine all the things going on appropriately with movement and emotion and pondering character motivation and the setting, sometimes I just pause and think about what is being described in my minds eye before moving forward in the text.