^
This rig is horribly configured.
280x should go for ~750kh each, 7950's should do 650kh each.
Furthermore his WU is horrible. Hashrate should reach ~3,45mh with WU = > 3000.
Happy tweakin!
There's only 8 minutes time in that cgminer instance, hardly enough time for WU to stabilize. I do agree, there should be more left in those cards, especially at those temps. Maybe splitting them to two separate cgminer instances?