Which CPU gives the best Monero profit per dollar spent?
A used AMD Ryzen 9 3900X or 5900X is a good starting point if you want the most Monero mining profit for each dollar you spend. Neither is a guaranteed winner: your purchase price, electricity rate, and the cost of the rest of your computer decide which CPU—the computer’s main processor—offers better value.
Why these CPUs are worth comparing
Monero uses RandomX, a mining method that favors CPUs. AMD Ryzen processors often perform well because they combine plenty of processing threads with generous L3 cache, a small pool of fast memory inside the processor.
RandomX needs roughly 2 MB of L3 cache per mining thread. More cores alone do not guarantee better results; memory performance and power settings matter too.
These are useful candidates to compare:
- Used Ryzen 9 3900X: Often attractive when the purchase price is low.
- Used Ryzen 9 5900X: Worth considering if its price is close to the 3900X and measured efficiency is better.
- Ryzen 9 3950X or 5950X: Potentially good value at a steep discount, but compare their extra output against their higher price.
- Newer Ryzen 9 models: Can offer stronger performance, but a newer motherboard and memory may outweigh the mining improvement.
Treat this as a shortlist, not a fixed ranking. Used prices and hardware condition can change the winner.
Compare the whole computer, not just the chip
A cheap CPU is not necessarily a cheap mining setup.
If you already own a compatible motherboard, upgrading its processor can offer much better value than building a new computer. Check the motherboard’s processor support list; some upgrades require a firmware update.
If you are starting from scratch, include:
- CPU, motherboard, and memory.
- Power supply, storage, and cooling.
- Shipping, tax, and any replacement parts.
For profit per dollar spent, divide your estimated daily net profit by your total upfront cost. A higher result means more daily profit for each dollar invested.
You can also divide upfront cost by positive daily net profit to estimate payback time. That estimate assumes conditions stay unchanged, which they will not.
Subtract electricity before picking a winner
Hashrate means how many mining calculations your computer performs each second. It measures speed—not profit.
Use this calculation:
Daily net profit = daily mining revenue − electricity cost − mining fees
Electricity cost is:
Wall power in watts ÷ 1,000 × 24 × your electricity price per kWh
Measure power at the outlet, not just the CPU’s reported power use. The motherboard, memory, fans, and power supply also consume electricity.
Check a live Monero mining calculator using realistic hashrate and power measurements. Avoid comparing one processor’s carefully tuned result against another’s default settings. If electricity costs exceed revenue, neither processor offers positive operating profit.
For browser mining, test before buying
Do not assume a benchmark from dedicated mining software applies to mining in your browser. Browser limits and the site’s implementation can produce very different results.
For MyAiMiner.com or another browser service, compare the actual credited earnings, fees, and outlet power use on your intended setup. Confirm what work your browser performs and how payouts are calculated.
The bottom line
Start by comparing used Ryzen 9 3900X and 5900X deals, especially if you already have a compatible computer. Buy only when realistic, after-electricity earnings justify the whole setup’s cost—not simply because a CPU has an impressive mining speed.
