There is a limit of your SATA, USB, M.2, and PCIe lanes that isn’t obvious. It’s defined by the processor and chipset combination, which has a fixed number of High Speed Input/Output lanes, equivalent to PCIe lanes. It is partly down to the mobo designers how these lines are wired, so what you get isn’t standardised, or quite what it seems.
Intel’s Z390, Z370, or H370 have 30 HSIO lanes. Your CPU, assuming you’re not running an X-series monster, supplies 16 more. The CPU lanes go direct to the main graphics card; on a gaming board, they run to two suitably spaced x16 PCIe slots, so if you run a two-card rig, each gets a x8 from the CPU. Ryzen chips have 20 spare lanes, so the right board can…
