AMD TRX40/X570 Series Motherboard models with PCIe 4.0 support
Supports PCIe 3.0 bandwidth for other RAID on CPU models.
Maximum numbers of M.2 SSD support will vary, depending on different CPU specs and PCIe bifurcation settings in different ASUS motherboards.
Please see the FAQ link for full compatible lists and further information:
https://www.asus.com/support/FAQ/1037507