[SOLVED] One of my Graphics Cards is just unresponsive and won't even work on its own

[Ceekaj]

So to start off here's my parts list:

1. Asus ROG strix b450-5 motherboard
2. 2x8 tridentz ram
3. amd ryzen 5 2600
4. Asus ROG strix rx580
5. Asus rog strix rx570
6. Corsair rm850

Now here's my problem. The rx570 doesn't work. I plug it in get the white light for the cable to say that's it's receiving power. When i turn the pc on the ROG logo lights up green(that was the color i set it to before i got the rx580). Now since i have two gpus i would like to set each up to a monitor. The rx580 sets up fine to its monitor but the rx570 doesn't. Sometimes it won't even be recognized by the computer. And when it is recognized I get the code 43 error. Now i have flashed the card before I just don't know what could possibly be wrong with it. I've tried taking the rx580 out and having just the rx570 but the computer won't even boot.

 

[Diddly]

Do you need both GPU installed? you can drive two monitors from a single GPU.