It's not the slot. It's amd lack of legacy bios support on the Rx cards. Best bet for that mobo is to stick to the 200/300 series cards. However, any of the decent amd cards are rediculously overpriced due to crypto-mining, so the better deal would be to go' team Green' instead, either a gtx1030 or gtx1050 or upto a gtx970/980 if the prices are good.