A card with low hashrate have an output? If it not, try to give output to this card. Your both cards are Power Color Red Dragon, right? Have you switch to compute mode? (if you are using Adrenalin). I can't give you more suggestions, cause we have a bit info about your system.
Hi,
The Powercooler one has a hashrate of 20 H/S when mining Expanse. BUT if I deactivate the Saphire card, the Powercooler ones jumps to 30H/S! I am in compute mode.
This leads me to believe that my MOBO does not have enough PCIe lanes to run both cards at the same time so, for some reason, the PowerCoooler's hashrate is affected.
Any more information, please let me know.