1. There is such thing as an e-ink screen that doesn't hold its image (and that the fastest-refreshing screens in R&D are this type). In other words, beware if someone says "this e-ink screen can refresh at 60FPS" as it might have sacrificed its power usage in order to achieve this (those screens are still useful if you only care about eyestrain/sunlight readability though). 2. 'Good Ereader' makes all his money selling the devices he reviews, which is a HUGE conflict of interest, AND HE IS NOT TRANSPARENT ABOUT THIS. Seriously, the dude generally either mentions it at the end of the video/article or not at all. Usually not at all. That's super scummy, and as such you shouldn't trust him or his videos. 3. Note that technically fast-refresh mode isn't getting 20 frames so much as refreshing a fraction of the screen at a time, so you have 10 pixels at 2Hz rather than each pixel refreshing at 20Hz. You could call it an interlaced refresh or dithered refresh, I'm not sure what the exact technical term is. The reason this matters is that we can't actually make electrophoretic pixels refresh any faster and they probably won't ever refresh the same pixel repeatedly at e.g. 60Hz - you're working against physics when you're shaking your ink up and down that fast, and you're talking about at least an order of magnitude more than you're getting right now.