Thanks for the confirmation.
Turns out I needed to put Option “Coolbits” “18” in order to override a vram size mismatch. That gives me the lesser video card claiming it has the same vram as the better videocard (bad behavior) and this:
[ 21.233] (WW) NVIDIA(0): Multiple display devices requested in MetaMode
[ 21.233] (WW) NVIDIA(0): “DFP-0:nvidia-auto-select,DFP-2:nvidia-auto-select”, but
[ 21.233] (WW) NVIDIA(0): only one allowed when SLI is enabled; ignoring extra
[ 21.233] (WW) NVIDIA(0): display devices.
Also, gdm-3.6.2 falls over itself and gives me a cursor over a black screen.