it can run 2 commands in 2 windows, for 1 card, just try, if you get error on any command let me know
The P100 video card is used remotely, I do not have a normal video card.
And how can iron be used if it is occupied by another process

The driver error itself will be.
in short i am guessing, your gpu engine commands inside program is default, and not useing full gpu power, as i said bitcrack used switches B T P , where you set compute thread, process, by this speed will increase more then 10x, study about bitcrack codes, hope u get success to increase more real speed