In the interest of full disclosure, that number is not my Bitfury gear exclusively. Have one rig running near 520 more-or-less stable, and another rig with 3 bad h-cards (2 DOA and 1 with a malfunctioning pot that won't volt above 0.127V and hashes at <2GHs) is stable at near 400. Have an RMA pending for the 3 bad cards after doing extensive testing last night.

 Will be doing more troubleshooting and tuning this weekend when I move the rigs out of their test environments.