Power Supplies Guide

1. What it is and what it covers

A PC power supply unit converts mains electricity into the regulated DC power required by the computer^★'s components. It is a critical reliability and safety component rather than an item where the cheapest adequate wattage is always the best choice.

2. Key facts and specifications

Compare continuous wattage, efficiency, ATX standard, connectors, modularity, physical size, protection features, warranty and suitability for the CPU/GPU. Modern PSU guidance includes ATX 3.x requirements for desktop platforms.

3. Practical guidance

Estimate the system's actual power requirement, then allow sensible headroom for transient loads and future upgrades. Check that the PSU has the correct native connectors for the graphics card and motherboard^★. Use only the modular cables supplied for that exact PSU model.

4. Suitability, choices and limitations

Lower-wattage units suit office systems; gaming^★ and workstation PCs with powerful GPUs may need substantially more. Modular units simplify cable management, while non-modular models can be cheaper. Efficiency ratings affect wasted energy and heat but do not by themselves prove overall quality.

5. UK-specific considerations

In Great Britain, electrical equipment^★ is covered by product-safety requirements, and current government guidance allows CE or UKCA routes for relevant products placed on the GB market under the applicable rules.

6. Safety, risks and cautions

Never open a PSU enclosure: capacitors can retain dangerous energy. Do not use damaged mains leads or mix modular cables between PSU brands/models. If a PSU smells burnt, sparks, trips repeatedly or behaves abnormally, disconnect it safely and seek professional advice.

7. Current sources and research

Intel's ATX documentation provides current platform guidance, including ATX 3.1 specifications. PSU selection should follow the complete system design rather than a generic wattage table.

8. Shopping^★ and buying considerations

Buy from a reputable retailer and prioritise a known-quality unit with appropriate protection, connectors, warranty and headroom. A reliable 750W unit can be preferable to an unknown 1000W unit.