How to choose a power supply (PSU) for a mining rig? How much wattage do you need?

Understanding Power Supply Efficiency Ratings

1. 80 PLUS certification levels—Bronze, Silver, Gold, Platinum, and Titanium—indicate how efficiently a PSU converts AC power from the wall into usable DC power for components.

2. A Gold-rated unit typically operates at 90% efficiency at 50% load, meaning less energy is wasted as heat and electricity bills remain more predictable during sustained mining operations.

3. Lower efficiency units generate excess thermal output, increasing ambient temperature inside mining farms and potentially triggering thermal throttling on GPUs.

4. Units lacking 80 PLUS validation often exhibit unstable voltage regulation under fluctuating GPU hash loads, leading to unexpected reboots or corrupted DAG file generation.

Selecting the Right Form Factor and Connector Compatibility

1. ATX PSUs dominate the mining space due to widespread availability and compatibility with standard motherboard trays and PCIe risers.

2. Some high-density rigs use redundant server-grade PSUs with EPS12V or 24-pin connectors, requiring custom wiring harnesses and careful grounding to avoid ground loop interference.

3. Each modern GPU—such as the NVIDIA RTX 4090 or AMD RX 7900 XTX—demands specific PCIe power connectors: dual 8-pin or 12VHPWR variants that must match the PSU’s native output configuration.

4. Using adapter cables introduces resistance points; daisy-chained PCIe splitters beyond manufacturer specifications risk voltage drop below 11.4V on the +12V rail, causing GPU detection failures in Linux-based mining OSes like RaveOS.

Calculating Real-World Wattage Requirements

1. A single RTX 4090 draws approximately 450W under full Ethash or KawPow load, but transient spikes can exceed 520W for brief intervals during DAG epoch transitions.

2. For a six-GPU rig using RTX 4090s, base load sits near 2700W—but adding motherboard, CPU, SSDs, cooling fans, and USB controllers pushes total system draw to roughly 3100–3300W.

3. PSUs should never operate continuously above 80% of rated capacity; selecting a 4500W unit provides headroom for aging capacitors and seasonal ambient temperature shifts affecting thermal derating.

4. Dual-PSU configurations are common in 8+ GPU setups, with one unit powering GPUs and the other handling system logic—this avoids overloading any single 12V rail and simplifies cable management across multi-rack deployments.

Thermal and Physical Considerations in Mining Environments

1. PSUs installed in enclosed metal racks without active airflow may suffer from internal temperatures exceeding 65°C, triggering automatic shutdown protocols even if output remains stable.

2. Industrial-grade units with IP20 or IP54 ratings resist dust accumulation better than consumer models, reducing maintenance frequency in warehouse-style mining facilities.

3. Modular cabling allows precise routing away from GPU hotspots, minimizing electromagnetic interference that could disrupt PCIe signal integrity across long riser cables.

4. Units with passive cooling modes often fail under constant load; mining-specific PSUs prioritize continuous fan operation with adjustable PWM curves tied to internal rail temperature sensors.

Frequently Asked Questions

Q: Can I use a gaming PSU for cryptocurrency mining?Yes, but only if it meets sustained 24/7 load requirements, features robust +12V rail design, and includes firmware-level protections against over-current events triggered by GPU power surges.

Q: Why do some miners prefer multiple lower-wattage PSUs instead of one high-wattage unit?Multiplying PSUs improves fault isolation—if one fails, only a subset of GPUs goes offline, preserving partial hash rate while replacement occurs.

Q: Does PSU quality affect mining profitability beyond wattage consumption?Yes. Voltage ripple exceeding 150mV on the +12V rail correlates with increased stale share rates in pools like Ethermine, directly reducing effective earnings per MH/s.

Q: Are there PSUs specifically designed for ASIC miners like Bitmain Antminer S19?Yes. Units such as the APW12 or Delta DPS-1600AB A deliver tightly regulated 12V@133A output with minimal transient response delay, optimized for the fixed-power signature of SHA-256 hardware.