Great discussions and info in this thread!
Just wanted to share my DL580 G7 build, wanted to run 11 cards, but settled with 9 after hours and hours of struggle.
Mining etherium at ~ 255MH/s. Ran Cryptonight at 1650H/s with 4x E7-8837, but stopped since i switch to SimpleMiner from hiveOS (had to prioritize gpu stability).
More pics here:
https://imgur.com/a/NzYLC