Just an update. Switched out the I/O board ($30 on eBay) on the DL580 that wouldn't boot with E7's and am now up and running. Using standard mem cartridges too, which is great!
I've also tested ROI coin with several memory configurations and the best hash is definitely achieved using all eight cartridges, using two 4gb mem sticks per. Haven't tried one yet, but really don't see a need to either. Setting huge_pages to 1024 is also optimal. Plus I've figured out how to achieve the same hashes with 8837's as with 4870's. A little tweaking on settings and all is well! These processors are pretty amazing.
You guys really should check out ROI coin. If you deposit coins for a one year period the returns are astronomical. It's a relatively unknown coin right now, so difficulty is very low. It also equates to the coin not being very high in value, but with the team of devs behind it and some time I'm totally confident this will change. And even if it doesn't increase in value after three years of rolling everything into deposits, which is unlikely as more people get on board, the returns are absolutely amazing!