AMD_bro is at it again
Ah, please forgive my rudeness (or maybe English misunderstanding for being a foreigner), I need some clarifications.
You mean RX 460 and 480, right?
If yes, and to add to the PSU adequacy discussion, the RX 480 requires a good quality 500W PSU as a minimum. Some say 450W but you already have 500W so let's keep it at this. By good quality I mean the rating and amperage. Continuous PSU 30amps and some say 34amps is the minimum for this card. If those are met and nothing else is on the way, you should be fine and things should run fine. Make sure the PSU is a good brand. Providing the brand and model of the PSU could help here.
Is the monitor/TV connected to the RX 480 directly.
The A10 CPU is actually an APU. It has a built-in GPU. First thing to do is make sure it's disabled in the BIOS if possible and that the monitor/TV is connected to the RX 480 video card, not the port on the motherboard.
One more thing, RX 480 is a much better performer than RX 460 if both are used at their fullest. If speed is fixed at 60FPS in a game that can get it on both cards, potential can be not be felt, tho.