Intel CPU i9-10900K: profitability and payback

What this rig is

Intel CPU i9-10900K is CPU. It runs RANDOMXMONERO and draws 125 W: about 3.0 kWh a day and roughly 90 kWh a month. Multiply that by your tariff and you get the power bill that arrives regardless of what the coin is worth.

In mining a CPU is needed by exactly one coin on our list — Monero: its RandomX algorithm is built so that ASICs get no advantage. On any other algorithm a CPU loses to everything.

Before you buy

• ·Wiring and sockets. A multi-kilowatt machine is not something you plug into an extension cord: it needs its own line, and in an apartment block also the agreement of whoever pays the shared meter.
• ·Noise and heat. An industrial ASIC means 70–80 decibels around the clock and kilowatts of heat that have to go somewhere. Home-friendly options — hydro versions and sound-proof enclosures — cost more and need space.
• ·Used units and warranty. The secondary market is tens of percent cheaper than new, but the machine already has hours behind it: ask where it stood and count payback with a margin for repairs.
• ·Pool and withdrawal. Income arrives through a pool: it has its own fee, payout threshold and schedule. Before buying, check that the coin has live pools and which exchanges you can withdraw to.
• ·The date of the calculation. The numbers here are live, but they describe today. Network difficulty almost always grows — assume the real payback will be longer than shown.