3xGigabyte 7970ocs, averaging 600-700mhs. 2xGigabytes pulling 660 watts at the wall. I'm trying CK's settings from this post,
https://bitcointalk.org/index.php?topic=88056.0, stating the cgminer is pretty much tuned default for 7970s. Reminds me of the old days of trying to eek out a little more mhz from cpus, and finally realizing oc'ing is a pain. I'm taking baby steps up from default settings.
Good luck and fortunes all!