Currently with just the 1070 mining this is my bat file.
setx GPU_FORCE_64BIT_PTR 0
setx GPU_MAX_HEAP_SIZE 100
setx GPU_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_SINGLE_ALLOC_PERCENT 100
ethminer.exe --farm-recheck 200 -U -S eth-us-east1.nanopool.org:9999 -O wallet.worker/email
Alright... looks like you are getting closer. Yeah, the bios settings for 1x... of course. And sometimes it gets finicky about gen1/2 speed stuffs too for the pcie slots.
For your bat file, try adding --opencl-device 0,1 at the end like this:
setx GPU_MAX_HEAP_SIZE 100
setx GPU_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_SINGLE_ALLOC_PERCENT 100
ethminer.exe --farm-recheck 200 -U -S eth-us-east1.nanopool.org:9999 -O wallet.worker/email --opencl-device 0,1,2
That would get you 3 cuda (Nvidia) devices. if you needed four of course it would just change to --opencl-device 0,1,2,3