Are this voltage readings normal(the +12V, 5V and 3.3 V)? Is this some problem of the software or is this realy a problem of the PSU?
Those voltage readings aren't correct. Your PC wouldn't be powered on if they were. Software readings aren't really to be trusted in the first place. HX850 has more than adequate voltage control, you don't need to worry about that.
This readings aren't from my computer, this a from a pc I help assemble for my father's work. This is the PSU used in it. http: // www . hardwareheaven . com/reviews/1644/pg1/cougar-powerx-550w-power-supply-review-introduction.html (remove the spaces, aparently guru3d didn't like this link) I realy wanted to put at least a Corsair CX, but as I explained above, it wasn't all in my power.
The readings are still incorrect and the voltages are probably just fine, like the hardwareheaven article shows. More results at legitreviews