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I have an B550 Aorus Pro AC motherboard with a Ryzen 5800X CPU. The first PCIE slot has my RTX 3080 GPU in it and both of the M.2 slots have drives in them. The second M.2 slot disables the second PCIE slot, it is either one or the other. That leaves the last PCIE slot, which according to the manual runs in x2 through the south bridge. I want to add another M.2 drive if I can, and my question is, if I get an adapter to put an M.2 drive in the last slot, will it work? I think not, since all the adapters I have seen say they need X4 at least, but I am not sure.
In theory most drives should support falling back to 2x mode now. In practice? Plug it in and try it out, it's hit and miss.
Thank you. I don't actually have the drive or the adapter yet, I should have specified that in my OP, my bad :( I don't really want to buy stuff and have it not work.