Why is RandomX hashrate per watt so important?

RandomX hashrate per watt tells you how much Monero mining work your computer does for the electricity it uses. It matters because a higher mining speed is not always a better result: if that speed needs much more power, you may spend more on electricity than the extra mining earns.

What the number actually tells you

A hash is one attempt at solving the mining puzzle. Your hashrate, measured in hashes per second (H/s), tells you how many attempts your computer makes each second. RandomX is Monero’s mining algorithm—the set of rules your computer follows to do that work.

To measure efficiency, divide hashrate by power use:

Hashrate per watt = hashes per second ÷ watts

For example, using made-up measurements:

• One setup produces 4,000 H/s at 100 watts: 40 H/s per watt.
• Another produces 5,000 H/s at 200 watts: 25 H/s per watt.

The second setup is faster, but it uses twice the electricity for only 25% more mining work. The first gives you more work for each unit of electricity you buy.

Why RandomX makes efficiency worth watching

RandomX favors CPUs, the main processors in everyday computers. But a CPU’s advertised speed or number of cores does not tell you how efficiently it will mine.

RandomX depends heavily on memory and cache, a small, fast storage area inside your processor. A useful sizing requirement is about 2 MB of L3 cache per mining thread. A thread is one stream of work your processor runs.

If you add more threads without enough cache or memory capacity to support them, power use may rise faster than hashrate. Likewise, pushing your CPU to higher clock speeds can require disproportionately more electricity.

That is why a slightly slower setting can be the better choice. You want useful mining work, not simply a processor running as hard as possible.

How it affects your electricity costs

Electricity is charged in kilowatt-hours (kWh), a measure of energy used over time.

A computer drawing 100 watts continuously uses:

100 ÷ 1,000 × 24 = 2.4 kWh per day

Multiply that by your electricity price to estimate its daily power cost.

Better hashrate per watt reduces the electricity needed for a given amount of mining work. It can also mean less heat and quieter fans.

However, efficiency does not guarantee profit. Your result also depends on Monero’s price, competition from other miners, fees, and hardware costs. Check a live mining calculator rather than assuming an efficient computer will pay for itself.

Measure the power you actually pay for

For a fair comparison, measure electricity at the wall socket, not just the CPU’s reported power. Your memory, motherboard, cooling, and power supply also consume electricity.

Keep your tests consistent:

• Use the same mining software and settings.
• Let temperatures settle before recording results.
• Compare sustained hashrate, not brief peaks.
• Change one setting at a time.

For browser mining, use the browser’s actual sustained results—not figures from dedicated mining software. Browser limits and implementation differences can change efficiency substantially.

The bottom line

RandomX hashrate per watt helps you choose the setting or computer that wastes less electricity. Focus on sustained mining work per watt, then check whether the expected earnings justify your total costs. The fastest setup is not automatically the most economical one.