Problem with asus rx 480 8GB Dual

Mb msi z170 krait 3..
4gb ddr4
Ssd 120gb
Cpu celeron g3900
6 hpu dual asus rx 480 8gb
2 x 700w psu coler master

When modded bios 1750 > 2000 msi afterburner dont show me core voltage and when turn on pc show me image aftter 20 sec.. version driver 16.11.2.. if i try unistal driver with amd clean utility dont show me image anymore..

If i leave orginal bios give me only 24MH and after 5 minuts gpu 3 and gpu 4 give me 0mh..

I try 3 graphics if i set memory core over 2000 mhz frozen pc...

How to moded this bios..
Why 2 show 0
Why cant over 2000mhz
Why frozzen