Question from Reader: I see that there is an 8 pin and a 6 pin on my graphics card. Should we use 8 pins on the rx 580 or rx 570?
Normally we would suggest using both pins to power your graphics card. However, if you know that your mining card uses less than 150 watts due to undervolting or your own modifications, then you can go right ahead and use the single 8 pin.
In fact, many people suggest doing this for mining and have reported some small incremental drops in wattage used. Regarding the decrease, your card may differ depending on the model, but test it to see if you notice anything different.