PCIe x8 NIC in PCIe x16 slot

I was looking into the card because the old GPU was just inserted into the slot and had no other power cables and 750 ti seems to be a similar

Therefore, some PCIe x16 slots might only have x8 PCIe lanes Usually, this wouldn't be problematic, even if you want to attach a GPU card to it

pcie 40 in 30 slot I'm new to MellanoxNVIDIA and am interested in MCX515A-CCAT As a 100 GbE card, I realize this card would need PCIe x16 to reach its

pcie 30 x1 slot I was looking into the card because the old GPU was just inserted into the slot and had no other power cables and 750 ti seems to be a similar