Using a PCIe x1 card in a PCIe x16 slot

pcie x4 in x16 slot   Dan pcie 20 x1 slot

So your adaptec x4 card will run at x4 in a x16 slot It's a good sign the x1 card works, but still isnt proof the x4 will work Ideally for

Yes, it works just fine, obviously it's only work at x4 speed I would check whether the x16 slot can handle the power load of the Lightning Fast Game experience: PCIe slots, Lightning Gen 4 x4 ; LAN: Upgraded network solution for professional and multimedia use Delivers a

bonus 123 slot login x16 ASRock B650E PG RIPTIDE WIFI AM5 ATX Motherboard, 4 slots DDR5, PCIe x16 Slot x4 NVME Speed up to Sponsored KingSpec XG 7000 2TB Yes, you can plug into 16x slot, but off course it will run in 4x speed Some motherboard even let you plug 4x card into 1x