i have 4 r9 280x Sapphire Dual-X OC version and my hashrates are appauling...what should be the proper cgminer settings...I can't get them above 580 or so...using risers and temperatures on all cards are well below 70.  Using latest Catalyst drivers and SDK from ATI all under Windows 8.1.  Really struggling here...any all help would be greatly appreciated.  Using a Corsair 1200ai PSU and Asrock H81 Pro BTC mobo.

Thank you