Hmm let's see, a single RTX3070 will draw 117 watts when mining Ethereum Algorithm and you said you have 4 pieces, that's like 468-500 watts for the four gpus, 850watt power supply should be enough for this setup 🤔🤔🤔💯💯
You're making the assumption that he is lowering the TDP... If he isn't the 220W per card far exceeds his PSU's power limit.