hmm im not undervolting... i think the cards (Gigabyte) are locked...are you sure my friend is running the exact same setting .... he has also two 1000W PSUs and for him its working nice...
but im going to measure it...
Try adjusting the voltages with MSI Afterburner beta version. I was able to drop the voltage from 1200 to 800 on each core with my 7990.