How to choose a power supply (PSU) for a multi-GPU mining rig?

Choosing the right PSU for a multi-GPU mining rig involves calculating total power draw, adding a 20–30% safety margin, and selecting a high-efficiency, single-rail unit with enough native PCIe connectors to safely power all components.

Aug 13, 2025 at 11:36 am

Understanding the Power Demands of a Multi-GPU Mining Rig

When building a multi-GPU mining rig, selecting the right power supply unit (PSU) is critical to ensure stable and efficient operation. The first consideration is calculating the total power consumption of all components, especially the graphics processing units (GPUs). Each GPU model has a different power draw; for example, an NVIDIA RTX 3060 Ti consumes around 200 watts, while an AMD RX 6800 XT may require up to 300 watts under load. Multiply the number of GPUs by their individual TDP (Thermal Design Power) to get the baseline GPU power requirement.

Do not forget to include the power draw of other components such as the motherboard, CPU, RAM, storage drives, and USB risers. A typical mining motherboard and low-power CPU (like an Intel Celeron or AMD Ryzen 3) may use 60–100 watts, and each PCIe riser can add 5–10 watts. Summing these values gives the total system power draw. It is wise to add a 20–30% safety margin to this total to prevent the PSU from operating at maximum capacity, which reduces efficiency and shortens lifespan.

Selecting the Correct PSU Wattage and Efficiency Rating

Once the total power requirement is calculated, choose a PSU with a wattage rating that exceeds this number. For example, if your rig draws 1,200 watts, select a 1,500-watt or higher PSU. This ensures the unit operates within its optimal efficiency range, typically between 50–75% load. Operating a PSU near its maximum capacity increases heat output and reduces reliability.

Pay attention to the 80 PLUS certification—this indicates efficiency levels under different loads. Options include 80 PLUS Bronze, Silver, Gold, Platinum, and Titanium. A Gold-rated PSU is often the best balance of cost and efficiency for mining rigs, converting over 90% of AC power to DC at typical loads. Higher efficiency means less wasted energy as heat, reducing cooling demands and electricity costs over time.

Evaluating PSU Form Factor and Physical Compatibility

Mining rigs often use custom or open-frame cases, so PSU size and mounting options must be compatible. Most mining motherboards support ATX power supplies, but some compact builds may require SFX or TFX units. Measure the available space in your mining frame to ensure the PSU fits.

Consider cable length and routing. PSUs with longer 24-pin motherboard and PCIe power cables make it easier to connect components in extended mining frames. Modular PSUs—where cables can be added or removed—are highly recommended. They reduce clutter and improve airflow, which is essential in multi-GPU setups generating significant heat.

Assessing the Number and Type of PCIe Power Connectors

Each GPU requires one or more PCIe power connectors, typically 6-pin, 8-pin, or 6+2-pin. A rig with six GPUs may need 12 to 18 PCIe power connectors depending on the models. Verify that your chosen PSU provides enough native PCIe connectors. Avoid using daisy-chained cables if possible, as they can overheat and pose a fire risk.

If the PSU lacks sufficient connectors, consider using PCIe splitters or PCIe power hubs, but ensure they are high-quality and rated for the load. Never overload a single PCIe cable beyond its 150-watt limit. Distribute the load evenly across multiple cables from different rails if the PSU supports multi-rail design.

Single-Rail vs. Multi-Rail PSU: Which Is Better for Mining?

PSUs come in single-rail and multi-rail configurations. A single-rail PSU delivers all 12V power through one circuit, allowing any connector to draw up to the total 12V output. This is ideal for mining because GPUs can draw power dynamically without being limited by per-rail amperage.

A multi-rail PSU divides the 12V output into multiple circuits, each with a current limit (e.g., 20A per rail). If a GPU pulls more than the rail allows, it may shut down. While multi-rail units offer better overload protection, they can be problematic in high-draw mining rigs. For this reason, single-rail PSUs are generally preferred in mining applications.

Ensure the 12V rail(s) can supply at least 80% of the PSU’s total wattage. For a 1,500W unit, the 12V output should be 1,200W or more. Check the PSU’s specifications sheet for this detail.

Reliability, Brand Reputation, and Safety Features

Mining rigs run 24/7, so PSU reliability is paramount. Choose units from reputable brands such as Seasonic, EVGA, Super Flower, or Corsair. Avoid no-name or OEM units, which may lack proper safety protections.

Look for essential safety features:

• Over-voltage protection (OVP)
• Over-current protection (OCP)
• Short-circuit protection (SCP)
• Over-temperature protection (OTP)
• Over-power protection (OPP)

These prevent damage during power surges or component failure. Also, ensure the PSU has active power factor correction (PFC), which improves efficiency and reduces strain on your electrical system.

Practical Steps to Install and Test the PSU in a Mining Rig

After selecting the PSU, follow these steps for installation:

• Power off and unplug the rig before connecting any components.
• Mount the PSU securely in the frame using screws or brackets.
• Connect the 24-pin ATX motherboard cable and ensure it clicks into place.
• Use separate PCIe cables for each GPU, avoiding daisy-chaining where possible.
• Plug in the CPU power cable (4+4 pin) if required by the motherboard.
• Double-check all connections before powering on.
• Boot the system and enter the mining software to monitor power draw.
• Use a watt meter to verify actual power consumption matches expectations.

If the system fails to start or shuts down under load, recheck cable connections and ensure the PSU is not overloaded.

Frequently Asked Questions

Can I use multiple PSUs in one mining rig?

Yes, it is possible to use multiple PSUs in a single rig, especially for large setups exceeding 2,000 watts. One PSU powers the motherboard and some GPUs, while another powers the remaining GPUs. Use a PSU controller board or jumper method to synchronize startup. Ensure both PSUs share a common ground and are connected to the same power phase to avoid imbalances.

What happens if my PSU wattage is too low?

An undersized PSU may cause system instability, random shutdowns, or failure to boot under load. It can also lead to overheating, reduced efficiency, and permanent damage to the PSU or connected components. Always size the PSU above the expected maximum draw.

Are server PSUs suitable for mining rigs?

Some server PSUs (like HP, Dell, or Lenovo) can be used if they are converted to standard ATX operation using adapter kits. They are often high-efficiency and reliable, but require careful modification. Ensure the converted PSU has the correct voltage rails and enough PCIe connectors.

How do I calculate the electricity cost of my mining rig?

Multiply the total wattage by hours of operation and divide by 1,000 to get kilowatt-hours (kWh). Then multiply by your electricity rate per kWh. For example, a 1,500W rig running 24 hours at $0.10/kWh costs $3.60 per day (1.5 kW × 24 × $0.10).