One-Sentence Definition
Undervolting mining is the practice of reducing the voltage supplied to your mining hardware (GPU or ASIC) to decrease power consumption and heat generation while trying to maintain the same hashrate.
Why It Matters for Solo Mining
When you’re solo mining, you might be running hardware for weeks or months before hitting a solo block, so every watt of electricity matters. Undervolting can cut your power bill by 20-40% without losing hashrate, which directly improves your mining profitability whether you hit a block tomorrow or six months from now. Plus, cooler hardware means less risk of thermal throttling during those long mining sessions.
How It Works
Mining chips (whether in GPUs or ASICs) come from the factory with voltage settings that ensure stability across all units, but most chips can actually run stable at lower voltages. By reducing the voltage through software (like MSI Afterburner for GPUs) or firmware modifications (for some ASICs), you decrease power draw and heat output. The key is finding the sweet spot where your hardware remains stable and doesn’t crash or produce invalid shares.
The relationship isn’t linear—you might drop voltage by 15% and only lose 2-3% hashrate, which is usually worth it. Lower voltage means your PSU doesn’t work as hard, your fans don’t spin as fast, and your entire rig runs quieter and cooler. This directly improves your joules per terahash (J/TH) efficiency metric.
The tricky part is testing stability—you need to run your mining software for several hours to make sure you’re not getting hardware errors or rejected shares. A crash during solo mining could mean missing your lucky moment!
Example
Let’s say your RTX 3070 normally draws 220W at stock settings while mining Ethereum. By undervolting the core to 800mV (from the stock 1000mV+), you might get it down to 130W while keeping 95% of your hashrate. Over a month of lottery mining, that’s saving about 65 kWh—real money that improves your odds of eventually profiting when you hit that block.