In my opinion, with that speed (7 seconds) there is a difference between a book and a computer monitor.
A book is physically in front of you, so if you were to "photoflip" it, your mind would still get all that information (I'd still recommend photoflipping 7 times or so, but that's just me).
With a monitor, you have to deal with the refresh rate of a monitor. Because a monitor can only refresh the screen so fast, if you were to scroll down the page faster than the monitor can refresh the signal, you would miss large portions of the book in the PR step (the upshot being scrolling through War & Peace on a computer monitor in 7 seconds is too fast).
The method I use for computer screens is to press the space bar or page down button repeatedly. Don't hold it down, just press it over and over again. What I usually do is time it as I do page flipping, but if you were to simulate the photoflipping process, you could probably just press it much faster.
The key is to press it repeatedly, because if you hold it down, the computer will scroll too fast and combine keystrokes, eventually leading you back to missing chunks of the text.
-Ramon http://razor.ramon.com