When creating a new world in Minecraft 1.8, huge portions of the world will appear as rapidly switching between how they look (dozens of times per second), and no actual terrain seems to generate in these areas. This has happened in every new world I've tried to make, and so I have not been able to use this version of Minecraft at all yet, as this bug essentially breaks the game for me. The pictures attached below are taken of the switching terrain in one area of a new world I created. They were taken from the same spot over the course of about a minute.