screen flashing 14w28a-29b

Everything starts to rapidly flash in white both all the blocks and the sky
I have had the problem since 14w28a until latest snapshot. my game is overall slow on loading chunks (30 FPS). It is not flashing everytime I am playing, some times it is even flashing when I have default resource and sometimes it is not flashing even when I have 128x. I do not know if it is computer performance that is triggering it. one time it got triggered when I was switching texturepack.