Do you think that with linux (like Ubuntu) i could increase a lot the Mkeys/s performance?
Not a lot, but at least you could avoid wasting CPU cycles on M$hit. 
I'd like to understand how to increase the Mkeys/s on cubitcrack/keyhunt-cuda.
I have a ASUSTeK CROSSHAIR VI HERO (AM4) motherboard with Multi-GPU SLI / CFX support :
2 x PCIe 3.0 x16 SafeSlots (CPU)
It means that i can install 2 GPUs.
Now I have one GTX 1060 3GB.
Can i add on the same motherboard another different video card like a 2080 or 3070 or 4090?
Or do i need to install one similar like another 1060 or 1080?
I read that 2 gpus can work in SLI mode, in cooperation mode.
Or is it better to make them work independently with these softwares?
The PSU is 850W so it should be enough.
What do you think?