I have a few of them working perfectly with 9 x 1080Ti's.
Out of box it will not work for that many cards, and the proper BIOS changes have to be made.
Step 1 is update the BIOS with EZFLASH via Internet. Step 2 is Enable Above 4G Decoding, and everywhere that has a PCIe drop-down (Gen1/Gen2/Gen3) you want all of them Gen2.
You can follow this video, it's for the Z270A but settings are exactly the same for Z370A.
I've used both Windows 10 and Ubuntu. Only real downside for mining is no cheap $40-60 CPUs in 8th gen; you have to get a i3-8100 minimum.
OS: Win10 FCU NoBloat edition I created with MSMG Toolkit
Video: Integrated video ALWAYS. HDMI dummy plug was one of the first stability breakthroughs I had back early 2017 before anyone had a clue about using them for mining rigs. It ensures windows desktop doesn't bind to first GPU it finds, which would otherwise interfere while it's mining, even over RDP.
NGFF to PCIe adapter on each M.2 slot
Afterburner, mining software, thats basically it.