Is it safe to plug it into a regular PCIe x16 slot on a desktop motherboard? The pic is HP NC375i NIC.

1 Answer

Yes. A larger PCI express slot fits all smaller PCI express cards. That means you can plug an x1, x2, x4 or x8 card into an x16 slot, x4 card into x8 slot, and so on.

The reverse is also true. You can plug a larger card into a smaller slot, for example x16 card into x8 slot, provided that the rear side of the slot is open. Of course now the card can only operate at the slower speed

Edit:

It turns out many people have actually asked this: HP nc375i Quad-Ethernet adapter, will it work in standard PCI-Express port (non-HP?), and there are people who tried to plug the card into an x16 slot and realized that the proprietary connector doesn't fit

The OP then cut the whole non-pin part away which results in the failure of the card

That's because the cut-out part contains metal and possibly some electronic components. I think if we grind the non-pin part (or simply cut the back of the x16 slot) to make it fit the x16 slot and cover the non-x8 part so the pins don't touch the x16 pins then it might work

The marked part above is the proprietary non-x8 part

However a simpler and non-destructive solution would be using an x8 riser card