Copper MOSFET heatsinks reduce VRM temperatures by up to 15°C on Bitaxe and NerdQaxe++ boards, extending component life and unlocking stable overclocks. This guide shows exactly where to place each heatsink on every board Solo Satoshi sells, with front and back diagrams for each device. Incorrect placement can short circuit traces, damage the VRM, and permanently destroy your miner.
Why MOSFET Heatsinks Matter for Bitcoin Home Miners
MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are the power switching components in your miner’s voltage regulation module (VRM). Every watt of power delivered to the BM1370 ASIC chip passes through these tiny components first. At stock settings, MOSFETs on a Bitaxe Gamma run warm but manageable. The moment you begin overclocking your Bitaxe, those same MOSFETs can spike operating temperatures, causing thermal throttling, hashrate instability, and premature component failure.
The ASIC chip gets all the cooling attention because AxeOS reports its temperature directly in the web dashboard. MOSFETs have no dedicated temperature readout on most open-source miner boards. Adding small copper or aluminum heatsinks to the correct MOSFET locations is the single most effective upgrade you can make.
Solo Satoshi carries the 52Pi Copper MOSFET Heatsink Kit, which includes 18 adhesive-backed pure copper heatsinks in mixed sizes. Pure copper conducts heat approximately 60% faster than aluminum of identical size, and the 8810-grade thermal adhesive holds firm even at elevated temperatures.
Critical Safety Rules for MOSFET Heatsink Installation
Placing a MOSFET heatsink in the wrong location can permanently destroy your miner. Follow these rules on every board, every time.
- Always power off and unplug your miner before installing or adjusting any heatsink. Allow the board to cool completely before handling.
- Only place heatsinks on flat MOSFET packages or directly on the PCB in areas that are prone to heat build-up. These areas are often rectangular, surface-mount components in the VRM zone of each board. They are clearly identifiable as flat black rectangles, typically 3mm to 5mm wide.
- Never bridge exposed pads, solder joints, or copper traces. A metal heatsink that contacts two conductive points simultaneously creates a short circuit. This can blow the VRM, fry the ASIC, or cause irreversible PCB damage. Always confirm that no metal edge or fin contacts neighboring components.
- Never place heatsinks on capacitors, inductors, or connectors. Only MOSFETs and voltage regulators benefit from direct heatsink placement. Placing conductive metal on other components risks shorting signal lines or power rails.
Misplacement may void your manufacture warranty. Please proceed with caution or reach out to your seller if you have any questions about MOSFET heatsink placement.
Board-by-Board MOSFET Heatsink Placement
Each picture below will mark the exact MOSFET and VRM heatsink placement zones, which has been tested via Infrared thermography (IRT). Place heatsinks only on the flat MOSFET packages within these marked zones.
Bitaxe Gamma 602
Nerdaxe Gamma
Bitaxe Gamma 650 Duo
Bitaxe GT 801
NerdQaxe++ Rev 6.1
MOSFET Heatsink Placement Summary by Device
| Device | ASIC Chips | Stock Power | Front MOSFETs | Back MOSFETs | Heatsinks Critical? |
|---|---|---|---|---|---|
| Bitaxe Gamma 602 | 1x BM1370 | ~18W | 2 | 2 | Recommended |
| Nerdaxe Gamma | 1x BM1370 | ~18W | 2 | 2 | Recommended |
| Bitaxe Duo 650 | 2x BM1370 | ~25W | 2 | 2 | Recommended |
| Bitaxe GT 801 | 2x BM1370 | ~43W | 0 | 4 | Recommended |
| NerdQaxe++ Rev 6.1 | 4x BM1370 | ~85W | 3 | 6 | Recommended |
Step-by-Step MOSFET Heatsink Installation
Step 1: Power Down and Cool
Shut down your miner through the AxeOS web interface or disconnect the power supply. Wait at least five minutes for all components to cool. Never install heatsinks on a warm board because the thermal adhesive bonds best at room temperature.
Step 2: Clean the MOSFET Surface
Use a lint-free cloth with 99% isopropyl alcohol to gently wipe the top of each MOSFET you plan to heatsink. Dust, flux residue, or fingerprints reduce adhesive contact and thermal transfer. Allow the alcohol to evaporate completely before proceeding.
Step 3: Size and Position Each Heatsink
Hold each copper heatsink above its target MOSFET to verify fit before peeling the adhesive backing. Confirm that no edge or corner will overhang onto an adjacent component, solder joint, test point, or copper trace. If the heatsink is too large for the available space, use a smaller size from the kit.
Step 4: Apply the Heatsink
Peel the blue film from the thermal adhesive. Align the heatsink squarely over the MOSFET package. Press firmly and evenly for five seconds. The 8810-grade adhesive bonds on contact, so reposition carefully if needed before applying pressure.
Step 5: Verify and Power Up
Visually inspect every installed heatsink from multiple angles. Confirm that no metal edges are in contact with any neighboring components. Reconnect power and monitor temperatures through the AxeOS dashboard. You should observe lower VRM-related thermal throttling and improved hashrate stability, especially under overclock loads.
Copper vs. Aluminum MOSFET Heatsinks
| Property | Pure Copper | Aluminum |
|---|---|---|
| Thermal Conductivity | ~401 W/mK | ~205 W/mK |
| Heat Absorption Speed | ~60% faster | Baseline |
| Weight | Heavier | Lighter |
| Cost | Higher | Lower |
| Best For | Overclocked miners, VRM hotspots | Stock operation, general use |
Copper is the better choice for MOSFET heatsinks on Bitcoin miners because the components are small, airflow is limited, and heat density is high. The 52Pi Copper MOSFET Heatsink Kit uses CNC-milled pure copper blocks that outperform aluminum alternatives in confined spaces.
Combining MOSFET Heatsinks with Other Cooling Upgrades
MOSFET heatsinks deliver the best results when paired with a comprehensive cooling strategy. The ASIC chip heatsink handles the primary heat load, but the VRM is the second-largest heat source on every open-source miner board. Here is the recommended cooling stack for maximum thermal performance:
ASIC Heatsink: Upgrade from the stock gold block to the Dark Horse Heatsink for up to 10°C reduction in ASIC temperature.
MOSFET Heatsinks: Apply the 52Pi Copper MOSFET Heatsink Kit to all identified VRM hotspots on front and back.
Thermal Paste: Replace stock thermal compound with Thermal Grizzly Kryonaut or Kryonaut Extreme (14.2 W/mK) on the ASIC for optimal heat transfer to the primary heatsink.
Rear Fan: A small 40mm or 60mm fan aimed at the back of the board provides active airflow across back-side MOSFETs, reducing temperatures by an additional 10 to 15°C. Browse fan options in our accessories section.
Proper Power Supply: An undersized power supply creates voltage ripple that forces MOSFETs to work harder. Use the recommended Mean Well power supply for your specific model. Follow the 80% Rule to keep continuous load within safe margins.
For a complete walkthrough of cooling configurations, visit Choosing the Best Cooling Solution for Your Bitaxe.
