The MB is an Auros B450, I get 28 MH/s from the card in the x16 slot but only 14 from the card in the x4 slot.
[/quote]

You don't have luck with the board.

the results now on my boards

Asus Z170 PRO GAMING (26,7+26,6+20,2)
Asus Z170 PRO GAMING (25,9+25,6+19,3)
MSI Z170A GAMING M7 (25,9+19,6+16,8)
MSI Z270-A PRO (27,6+20,6)
Asus P8Z68-V PRO (22+22+15,8)
AsRock A55 Pro3 (25,2+16,0)
AsRock 880G Extreme3 (19,5+19,5+15,2)