Originally Posted by kodomo
This option serves the purpose to save battery power rather than gaining speed.
If you consider how an E-Ink display works (there's an explanation in the mobileread wiki), you can figure that there's a difference in power needed
- to update parts of the screen
- to update the whole screen, accepting visible artifacts
- to reset the whole screen to avoid artifacts.
This option sets the frequency to do the latter.
If changing this setting makes any difference in speed, I'd reckon it is in a completely different order of magnitude (much smaller than what you're looking for).