Here's a new slogan I just came up with: digging on the net will typically just dig you a hole!
So, there is a problem with your setup, but it's not that the slot is x8, it's that it's x4, which doesn't support SLI. Somehow you ended up with the wrong NVLink bridge, so yes, that is in fact a paperweight, and not a very good one, because it's super light!
You need to have your video card in the slot where your Optane drive is, and then you need to move the Optane drive to the empty slot above it (you could also put it in the empty slot that will become available once you shift the PNY card up, but that will block the PNY's first fan).
Remember how I said it was critical that you have a dual slot card in the top slot, which is why I liked the EVGA Hybrid model so much? This is the reason. There is only one possible setup for SLI on the Gigabyte board (and most boards), and to use it along with Optane, you needed at least one of your GPUs to be dual-slot, rather than triple-slot.
The good news is that the only thing you need is a new NVLink bridge: this
EVGA 3-slot model.
