Asus 390 TUF gaming MB Will not run 6 GPU’s

I am trying a new MB. A Asus TUF 390. It has an i8700k cpu and 2ea 1000watt psu’s. I have replaced all the risers, I have tried different cards. But I can’t get it to run 6 cards. Only 5. I am very new to this style MB and not sure what the bios settings should be. I tried setting them to my other Asus MB bios settings. Any help would be appreciated. The goal of this project was to try to use cpu to mine also.

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