These speed tests were filmed at actual web page rendering times. If you're interested in the technical details, read on!
Equipment used:
"Why does allrecipes.com in the potato gun sequence appear at once, and not the text first and images second? And why does it appear to render from bottom of the screen to the top?"
Chrome sends the rendered page to the video card buffer all at once, which is why allrecipes.com appears at once, and not with the text first and images second. Chrome actually paints the page from top to bottom, but to eliminate a shadow from the driver board, we had to flip the monitor upside down and set the system preferences in Windows to rotate everything 180 degrees, resulting in the page appearing to render from bottom to top.
"Why does the top one third of the page appear first on the weather.com page load?"
Sometimes only half the buffer gets filled before the video card sends its buffer over to the LCD panel. This is because Chrome on Windows uses GDI to draw, which does not do v-sync.
"The screen wipes are so smooth - how was that achieved?"
The screen wipes up in a gradated wipe because LCD pixels take around 10ms to flip and gradually change color.
For behind-the-scenes footage of how this video was made: http://www.youtube.com/watch?v=_oarMXGq3gI
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