maybe two x4 links out of an x8-wired x16 slot. Now, there’s an alternative, and it’s PCIe switches – these are hefty chips which present a PCIe device interface to your host, and multiple ...
PCIe x4 and x8 cards can draw up to 25W from the motherboard's slot, while x1 cards are limited to 10W unless configured as a 'full-height' or 'high-power card' to pull the aforementioned 25W.