Don't want to buy an over-spec'd NVMe; what's the max speed for an PCIe 2.0 x4 M.2 slot? : r/buildapc
Amazon.com: KALEA-INFORMATIQUE PCIe 2.0 x4 Controller Board for M2 SSD PCIe and/OR Sata - with 12V and 3.3V Support - 1 Port for M.2 SATA + 1 Port for M.2 PCIe! : Electronics