So this morning I took the time to move my 4 1080tis from biostar 12 GPU board (which was a pain to get all 4 cards working) to the octominer board.

It was very easy to get up and running and I'm impressed.  A little troubleshooting, but no pulling out my hair trying to figure out why the cards wouldn't work with risers.  Also, I didn't have to make any modifications to the octominer board bios before I started hashing.  Right now running Windows 10 with Awesome Miner, (using a SATA SSD) but might try hiveos sometime.

Only have 4 cards and left a space between them, but I could see it be quite tight with all 8 cards.

Would be interested in hearing folks that are using all 8 1080ti cards "open air" without a case - how are you getting rid of the heat? Right now I just have a box fan on top.

Here's a pic of my setup (pardon the mess)
https://www.dropbox.com/s/nlwimn63m5l8grb/octominer.jpg?dl=0