Asus H270 Pro motherboard issues

Hi, I have a Asus prime H270 Pro motherboard with the latest bios (0607 x64)

I don't see any option to enable 4G decoding. And any search I run I only see people using the H270 Plus MOB. Do I have the wrong motherboard? I was building my first rig and planned on running 6 rx460 cards but I have only get 3 to successfully boot into windows. My power supply is a evga 850 p2.

Any advice would be greatly appreciated!

Thanks,

Try this in bios,should be there in settings :

ADVANCED -- SYSTEM AGENT (SA) CONFIGURATION --- ENABLE 4G DECODING