For everyone with mobility (switchable) video cards, and having white screen at launch. Turns out that wow is using dedicated gpu fully, and you can play wow normaly, if you are not changing setting while in game, because that process everytime hangs game for about 5min, so better change settings just one time, and leave them be.
To play, you need to 1) disable Opengl in gpu settings (Opengl not supported any more), and; 2) when launching game, just wait for 15mins while white screen; 3) don’t use settings while in-game, because it will hang game everytime for 5mins.
Just wanted to share this, if anyone still wondering.
Regards