PCIe x4 into x16, but what about the transfer speeds?

PCIe x1 x4 cards in x16 slot pcie x4 in x16 slot Lightning Fast Game experience: PCIe slots, Lightning Gen 4 x4 ; LAN: Upgraded network solution for professional and multimedia use Delivers a pcie 20 x16 slot A PCIe x16 slot provides powerful graphics card support The motherboard offers three slots, one of which is a PCIe x4 slot

pcie gen 4 in gen 3 slot IPCIE16XD11 is Multiple SFF-8654 x4 to PCIe x16 Slot Expansion with Broadcom MegaRAID 9560-16i, 9560-8i, 9580-8i8e, 9500-16i, 9500-8i,