Heat, noise and dust: running a rig where you live
Why a rig heats a room by its full wall draw, why no fan beats warm intake air, and how to handle noise, dust and damp when mining at home.
The two facts that decide where a rig can live
Nearly every problem with a rig in a house comes back to one of two facts. Neither is a matter of tuning.
- Every watt a rig draws from the wall leaves it as heat. Not most of it, not roughly, all of it. Computing does not use up energy, it moves it around, and the energy ends up in the room.
- Air cooling cannot bring anything below the temperature of the air reaching it. Fans change how far above the intake air, the air entering the rig, a card sits. They cannot change that floor.
So a rig pulling 1,200 watts is a 1,200 watt heater that happens to compute. It is the same as a small electric fire running all the time.
What this means for a hot rig
The first fix for a hot rig is nearly always cooler intake air, not a faster fan curve. Turning fans up in a room that is already warm buys a few degrees and a lot of noise.
A rig that ran perfectly all winter can throttle in July with nothing changed. Throttling means the card slows itself down to cope with heat. The room got warmer, so every card got warmer by the same amount.
A small closed room is the worst place for a rig. The heat has nowhere to go, so the room and the intake air warm together. The cards climb until they throttle.
A rig in a cupboard does not need a better cooler. It needs the cupboard opened.
Where the heat should go
- Out of the room, not around it. A fan that stirs the air in a sealed room raises the average temperature. The heat has to leave through a window, a duct, or an open door to a much larger space.
- In one side and out the other. Cold air in low, hot air out high, with the rig between them. Cards that breathe in their neighbour's exhaust are why the middle card in a row is always the hottest.
- Somewhere useful in winter. A rig really does heat a room. If you were heating that room anyway, the electricity does two jobs. This is the one seasonal argument in mining that actually holds.
- Somewhere else in summer, if you can. A room that has to be cooled costs you twice: once to make the heat and again to remove it.
How loud is a rig, and what helps?
A rig is loud, and it is loud all the time, which is different from just loud. Fan noise rises steeply with speed. The last few hundred revolutions per minute cost far more noise than they buy in cooling.
That is one more reason to lower the intake temperature instead.
Sustained noise is a health question, not only a comfort one. Workplace exposure limits start counting at levels a rig in a small room can reach. If you must raise your voice to be heard next to it, do not sleep in that room.
What actually helps, roughly from most effect to least:
- Put it somewhere else.
- Undervolt it, so the fans have less to do. Undervolting means running the card at a lower voltage.
- Replace loud fans with better ones, not with more of them.
- Mount it so nothing resonates.
- Only then consider enclosing it. That trades noise for heat and usually loses.
How to keep dust out of a rig
A rig is an effective air filter that nobody empties. Dust settles on heatsinks and insulates them. The card runs hotter for the same load, and the fans work harder to achieve less.
- Filter the intake rather than the whole rig, and clean the filter instead of the rig. This single change saves the most work.
- Aim for more air coming in than going out. Then what leaks in through gaps is filtered air, not dust.
- Blow dust out with compressed air, holding each fan still while you do. A fan spun by air becomes a generator and can put voltage where it does not belong.
- Never use a household vacuum on it. It brings static, and enough suction to move small components.
- Keep it off the floor, and not on carpet. That is where the dust is.
- Once a month is a reasonable interval in a normal home. Clean more often if anyone smokes or there are animals.
Damp and cold: the risk in garages, sheds and basements
A garage, shed or basement solves the heat and the noise at once. But it brings one risk a warm room does not have: condensation.
Condensation forms when a surface is colder than the dew point of the air around it. The dew point is the temperature at which water comes out of the air. A running rig stays warm and is generally safe.
A rig that sat switched off in a cold space can have water on it before it starts. So can one carried from the cold into a warm room.
The practical rules:
- Leave it running rather than switching it on and off in an unheated space.
- Let cold hardware reach room temperature before powering it on.
- Keep it off a cold floor.
- If the space is genuinely damp, deal with the damp, not the rig.