35ºC you must live in north pole...
i think rx460 could do similar results. I'm getting 11.8 mh/s out of the box. no oc, no bios.
I put my rigs in refrigerator )) I did unlock, overclock and bios on rx460. I could get only 14.5 mh/s for Solo mining. On dual they are very unstable.
But, RX560 are better in performance and stable.
https://image.ibb.co/jjRYxv/Capture.png
could you share your BIOS? Owning RX460 and also 560, before two weeks I had 13mh/s on stock with the RX560 now I have only 11,9mH/s a Kind of strange. Maybe it's caused by the Driver. Which one are you using?
Could you please also provide you OC Settings for both Cards?