# nvidia-smi -L
GPU 0: GeForce GTX 1070 (UUID: GPU-a66c5cbb-a541-a3d7-845c-f8c0c021ae71)
GPU 1: GeForce GTX 750 Ti (UUID: GPU-db546e26-f6d5-5345-45e4-434e0bfb4f62)

sudo Xorg :2 vt8 -config xorg-second.conf  -configdir conf.d

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    BusID          "PCI:3:0:0"
    VendorName     "NVIDIA Corporation"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Coolbits" "4"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection