An interesting bit here (from the last comment): > I came across an interesting example of perception vs. reality while designing a small text editor: When scr

An interesting bit here (from the last comment): > I came across an interesting example of perception vs. reality while designing a small text editor: When scrolling the text horizontally in a window we would refresh the text by redisplaying each line starting at the top. This resulted in a wave of text rippling down the screen, and many complaints that the screen refresh was too slow. The remedy was to scroll the bits already on screen and then redisplay each line from the top. The second implementation was actually slower than the first because we incurred the overhead of scrolling the bits before we even started to display the new text on the screen. However, the perception was that there was an immense increase in speed. We stuck with the second implementation because it increased the overall satisfaction of the user even though it actually decreased the throughput of the product. The commenter is actually subtly wrong about what's going on here though (but fortunately does the right thing by focusing on user satisfaction). Without scrolling the bits first there's a "wave" artifact. That movement will prevent most users from starting to get their bearings on the new position of the content until after the wave is done. Scrolling the bits first hides the wave and allows the user to start getting their bearings as soon as the bits are scrolled. Newly revealed content does take longer to appear, but if scrolling the bits is significantly faster than the redraw the difference is small and the user is able to process the new content more quickly overall by already having their visual bearings.