Minecraft world loaded in 1.8pre3 and was supposed to render fine like it did for all other versions
World loaded fine but after a radius of a few chunks it wasnt loading the graphics correctly, artefacts popped up everywhere, ground invisible, randomly displaying various parts of the surrounding area. For instance, it would go between showing a ravine, a lake, a forest, and some lava, among other scenery. This effect was tiled all around the spawn area, which was unaffected.
To reproduce this effect I assume you must be on Windows 8, create a new world in 1.8pre3, and then start changing all the video settings from high to low and back again.