I got 8 gpus (8x580s Strix) running on Z270P.. you need to be careful with how you install everything and making sure updates are turned of, a lot of the times, your drivers are updated, and theyre not compatible with 8 gpus. it took us 1 day but we finally managed to do it, and replicate it on 2 other rigs.

wts guide for 0.01613 btc, please pm