I've been a GPU miner since 2013. Here are 4 different times when I built rigs for mining Ethereum. Power cost was 10 cents.
- Late 2017: $220/card (RX 570 4G), 100-125% ROI
- Early 2018: $370/card (RX 570 4G), -50% ROI
- Early 2019: $140/card (GTX 1060 6G), 400%+ ROI
- Late 2021: $1300/card (RTX 3080L), 20% ROI
Here is what the mining calculators said:
- Late 2017: 400-500 days for payback
- Early 2018: 300 days for payback
- Early 2019: 600-700 days for payback
- Late 2021: 300-400 days for payback
What happened? The case in which I made the
most profit was when Whattomine said it was the
least profitable. When Whattomine showed rosy projections of payback in 1 year, I made the least profit.
The most important factor in profit, especially for GPU mining, is buying the equipment
for a reasonable price, then selling it for a
reasonable price later.
I think $425 for an RTX 3060 today is a decent price, considering PoS has been pushed back. Beware that the price was $600 just 2-3 months ago! There is no way anybody made $175 of mining profit in the last 3 months, even with free power.
So don't blindly trust the calculators!