I’m thinking of getting a 10 GbE NIC for my computer, but I only have a spare x4 PCIe 3.0 slot. The NICs with x4 connectors are all around $90-100.

I can get an older Intel one for under $40 but they all come with x8 PCIe 2.0 connectors. I can physically plug them into my x4 PCIe 3.0 slot because it has an “open back”, so they will fit and I know they will still work.

But the question is - will I get full speed. x4 PCIe 2.0 should be able to do around 2 GB/s, so even after overheard it should be able to deliver the ~1.2 GB/s that is 10 gigabit. But is it wired in a way that it can do that is the question.

What do you think, should I try it?