I've NEVER seen a "working on more than 6 reliably" report.
Checking in as another 8x Vega miner, though on the ASRock H110 - 15,760 of that sweet Monero hashrate, every second.
On topic, I'm glad I found this, as I was actually expecting to be able to run 18 RX570s on this thing. Though is the limitation the motherboard or Windows?
(Edit: After seeing other threads, I see the mobo won't even POST with over 13 of the same card... very weird, I definitely don't understand how any motherboard would care which GPU manufacturer is being plugged in, though someone mentioned potential display outputs, which is an interesting thought.)