Thermal Paste
Thermal paste is the heat conducting layer between a chip and its heatsink. It fills the microscopic gaps that heat cannot otherwise cross.
Why thermal paste is needed
A chip surface and the base of a heatsink look flat, and at the micron scale they touch only in places, with air in between that barely conducts heat. Paste pushes the air out and builds a continuous path for heat. The layer has to be thin: too much paste works worse than a correctly applied minimum.
In a miner the paste lives in far harsher conditions than in a computer: the load runs around the clock, temperatures are high, heating and cooling cycles are few, and time under load is measured in years. Over time it dries out, loses conductivity, and chip temperatures creep up at the same settings.
Dried paste looks like an asic going downhill: hashrate holds, temperatures sit above last year's at the same weather, fans run louder, and the firmware starts dropping frequency in the heat. Replacing the paste brings the miner back to its old figures, and it is one of the cheapest maintenance jobs there is.
Quick reference table
| What it does | carries heat from the chip to the heatsink |
| Layer | thin, too much hurts |
| Sign of wear | higher temperatures at the same weather |
| When to replace | when a board is opened and when temperatures climb |
| What else to check | clean heatsinks and the fans |
When replacing it makes sense
Rule out dust first. A clogged heatsink gives the same symptoms, and blowing it out takes ten minutes and no disassembly. If temperatures did not come back after cleaning, then it is about the paste.
Replacing paste means taking a board apart, and on an asic under warranty a service center does it: signs of intervention usually void the warranty. On older asics the job is routine, and we do it together with general maintenance.
Do not chase exotic compounds. Ordinary good paste, applied properly and thin, gives a better result than an expensive one laid on thick. Liquid metal in a miner has brought us more trouble than benefit.
An example from the bench
An asic from 2022 started dropping frequency in summer, with temperatures about ten degrees above the previous season and hashrate sagging in the pool. Blowing it out helped in part, and a paste change brought back the spec figures. The labor cost an order of magnitude less than a month with part of the revenue gone.
Related terms
Where to go next on the site
Hardware
- ASIC Chip and Hashboard knowledge base
- ASIC Miner knowledge base
Guides
- Bitmain knowledge base
Questions and answers
How often should thermal paste in an ASIC be replaced
By condition rather than by calendar. The reference point is temperatures at comparable weather: if they crept up after the heatsinks were cleaned, it is time.
Does new paste add hashrate
There is no direct gain. It brings the asic back to spec temperatures, which removes the frequency drop in the heat, and hashrate stops sagging.
Can you change the paste yourself
Technically yes, and it takes care plus an understanding of how to pull the heatsinks off. On an asic under warranty a service center does it, and doing it yourself costs you the warranty.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .