To all UX3405 owners with overheating laptop, I replaced a thermal paste and problem is gone, more info here https://www.reddit.com/r/ASUS/comments/1d44th5/comment/l6coivy/
To ASUS stuff - check the QA of your laptops, there's a problem with the thermal paste out of the factory. Might be applicable to other new Asus laptops. If someone's interested, have a full video of it.
