2 NVMe SSD's which slot to put OS on and does it matter?

When did slots become commonplace? And NVME slots? m 2 nvme ssd slot Also supports PCIE x1 bus slot The NVMe PCIe card allows you add PCI-e NVME SSD to your motherboard without slot, perfect solution m2 slot screw As people pointed out, your motherboard have only one PCIe NVMe capable slot So only one NVME drive natively for this board

m2 slot ZEBRONICS G41+128 GB SATA SSD + 4GB starlite DDR3 RAM with Core 2 Duo CPU Combo set Motherboard ZEBRONICS ZEB-H81M2 with PCIE NVMe Slot