After much research and troubleshooting I have found a solution to my RX480 issues. The original clock speed of the RX480 when purchased was set at 1288MHz from XFX. My RX480 has a single 6-pin power connector. There were thermal and performance issues with the factory overclock and original bios, so I flashed the RX480 bios to reference design specifications thinking that 1266MHz would surely resolve any thermal and performance issues. The bios flash did nothing to the thermal and performance issues encountered using the reference design specs. I then decided to flash the bios using another bios file for the same XFX design dated June 29, 2016 with a GPU clock of 1328MHz. Much to my surprise the bios flash not only resulted in lower temperatures, but a lower power draw as well and now idles at 39c.
Gaming performance is much better compared to the other bios files and all issues encountered with this XFX RX480 8GB has been resolved with the current bios flash. If you are currently experiencing issues you may want to flash the GPU bios to see if any improvements can be obtained via flashing the bios. Note: Updating a GPU's firmware should only be performed if you are experienced and familiar with flashing the bios.