How to choose the right PSU wattage

Estimate the complete system draw

Add the expected CPU and GPU power, then allow for the motherboard, memory, storage, cooling, fans and connected devices. The graphics card usually has the largest effect in a gaming PC.

Leave sensible headroom

A common practical target is to keep expected sustained draw below roughly 80 percent of the PSU rating. This is not a universal rule, but it gives room for component variation, transient loads and future additions.

Follow the GPU manufacturer recommendation

Check the recommended system power and connector requirements for the exact graphics card model. Factory-overclocked cards can have different requirements from reference specifications.

Check connectors before wattage

Confirm the required PCIe or 12V-2x6 GPU connectors, CPU EPS connectors and enough SATA power connections. Avoid unsafe adapter combinations and follow the power-supply and graphics-card instructions.

Quality and protection features matter

Choose a reputable modern unit with appropriate protections, a useful warranty and independent technical reviews. An efficiency label describes efficiency, not overall build quality by itself.

Typical starting ranges

• Basic or integrated-graphics PC: often 400-500W
• Mid-range gaming PC: commonly 550-750W
• High-end gaming PC: often 750-1000W or more

These are starting ranges, not guarantees. Always calculate using the exact CPU, GPU and power limits in your build.

Common PSU mistakes to avoid

• Buying only from the wattage number and ignoring connector requirements.
• Using cables from a different modular power supply.
• Forcing a connector that does not fit naturally.
• Forgetting that large factory-overclocked GPUs can have higher power limits.
• Choosing a poor-quality unit just because it claims a high efficiency rating.