MoP booting/loading time

Hello,

Does anyone have these problems / or knows a fix about the following Mists of Pandaria problems?

1. When I run the game, it starts it and turns screen black for 20-30 seconds before loading the menu etc. (This wasn't happening before 5.4.8.)
2. When loading zones it loads at the same speed as it did on my old pc which was utter crap.

I've tried re-downloading it, clearing cache, changing priority in task manager and running the game as administrator, and none of these helped the problem.

Thanks.

Hmm, anyone?