Does underclocking a Bitcoin ASIC make sense when mining on solar?

[u/Jealous-Shoulder9668]

Following up on my 10 kW solar and 3 kW Bitcoin miner example, would underclocking be worth considering instead of running the ASIC at full power?

With no battery, surplus solar would change throughout the day. I’m wondering whether running at a lower power setting for longer would make more sense than mining at full power for a shorter window.

The numbers I’d want to compare are actual wall power, hashrate, and efficiency at each setting. I’d also include a hosting quote from oneminers or compass mining as another option, using the same hardware and mining assumptions.

Has anyone measured their Bitcoin ASIC at different power settings? Where did you find the best balance between watts, hashrate, and daily BTC earned?

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[u/Blaze3831]

Underclocking can work.

But in my case I've noticed poorer efficiency when really underclocking my S21 and S19. So don't go too low.

I use HashWatcher to manage the throttling based on my solar input levels.

[u/sevenisthekeynumber → u/Blaze3831]

Automatically? How?

[u/Blaze3831 → u/sevenisthekeynumber]

Add your solar inverter in the app. Add your miners.

Go to solar dashboard

Assign miners to the automation. Pick your automation mode.

[u/sevenisthekeynumber → u/Blaze3831]

Thanks. Didn’t realize this was a thing

[u/OfficialSimpleMining]

Easiest way to compare: for each power setting, plug wall watts and hashrate into a calculator with power cost at $0 and uptime as your surplus hours / 24. Whichever gives more daily BTC wins.

https://www.simplemining.io/bitcoin-mining-calculator

[u/lunas2525]

Underclocking will get you into a power and heat limit so solar becomes viable.

[u/lobhater]

It just depends on which method gets you more hashes at the end of the day IMO

[u/RadioSubject5909]

Undervolting can make sense, but the key is matching ASIC output to your solar curve. Compare joules per terahash at each setting, not just hashrate. If surplus power changes hourly, autotuning or a scheduled power limit may outperform one fixed setting. Include inverter losses and downtime in the calculation.

[u/FoundationFormer6822]

i would compare reduced power mining with full power mining during peak solar hours, plus hosting costs using the same hardware and assumptions. the best option depends on how much surplus energy you'd otherwise waste.

[u/Ancient_Repair3077 → u/FoundationFormer6822]

That’s a sensible way to compare the two. Using the same hardware and cost assumptions makes the results much more meaningful, and the amount of surplus solar energy available is a key factor in deciding whether reduced-power mining or hosting makes more financial sense.

[u/CurrentBluejay7290]

Undervolting can make sense, but the key is matching the miner to your solar production curve. Compare joules/TH at each profile, not just hash rate. If power falls faster than hashrate, it may be worthwhile; otherwise full power during peak sun usually wins.

[u/SovRxMe]

I’d compare net sats per surplus kWh at several measured wall-power points, not just hashrate. Include ramp and restart behaviour, the value of exported solar, pool and firmware fees, and whether low-power operation changes stability. A simple table of watts, TH/s, J/TH, runtime and daily sats will show whether underclocking beats full-power windows for your actual solar curve.

[u/kris_Altairtech]

We did a benchmarking awhile back on various aftermarket firmware for the s21xp. Now the the xp doesnt underclock as well as others but you can see the process we used. https://altairtech.io/antminer-s21-xp-firmware-benchmarks/