I have a rig with 6 AMD RX470, Asus Prime Z270-A Motherboard and Windows Pro 10 (64). I am gettin 19.8 Mh/s per card mining ethereum. My other RX470 rig gets 21.9 Mh/s. Same cards, same brand, different hash rates.

There is something wrong with the 19.8 Mh/s rig, because Claymore does not report the temperature and fan velocity of the cards. Also sometimes the pc freezes and MSI Afterburner does not work.Can't figure out where is the problem. Card driver is 171.1024. The rig with 21.9 Mh/z hashrate has Driver 162.4

Can the problem be in the card driver? If so, how do I uninstall and install the correct driver?