Why do I need headroom on my PSU?

A 20% headroom buffer ensures your PSU runs efficiently (80-90% load is the sweet spot for most PSUs), handles transient power spikes, and leaves room for future upgrades.

What happens if my PSU is too small?

An undersized PSU can cause random shutdowns, system instability, boot failures and in extreme cases permanent damage to components. Always size up rather than down.

Does 80 Plus certification matter?

Yes. 80 Plus Gold or higher rated PSUs waste less energy as heat, run quieter and typically use higher-quality components. They also lower your electricity bill over time.

How much power does a modern GPU need?

Mid-range GPUs (RTX 4060 class) draw about 150-170W. High-end cards (RTX 4080/4090) can draw 300-450W under load, with brief spikes even higher.

Should I get a modular or non-modular PSU?

Modular PSUs let you connect only the cables you need, improving airflow and cable management. Semi-modular is the best value option for most builders.

What happens if my PSU wattage is too low?

An underpowered PSU can cause system instability, random shutdowns, crashes under load, and potential data loss. Always choose a PSU with at least 20 percent headroom above your estimated total draw.

Does 80 Plus certification matter for PSU efficiency?

Yes. 80 Plus certified PSUs convert at least 80 percent of AC power to DC, wasting less energy as heat. Higher tiers (Bronze, Gold, Platinum, Titanium) indicate better efficiency.

Should I get a modular or non-modular PSU?

Modular PSUs let you connect only the cables you need, improving airflow and cable management. They cost more but are worth it for cleaner builds.

How long do PC power supplies last?

A quality PSU from a reputable brand typically lasts 7 to 10 years under normal use. Many premium units come with 10-year warranties.

Do I need more wattage for overclocking?

Yes. Overclocking increases power draw significantly for both CPU and GPU. Add 10 to 20 percent extra wattage above the stock power estimates when overclocking.

Last updated: 28.03.2026

PC Power Supply (PSU) Calculator

Find the right PSU wattage for your PC build. Select your CPU, GPU, storage and peripherals to get a recommended power supply size with 20% headroom.

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Select your components to find the minimum recommended PSU wattage.

Recommended PSU

450W

Total draw: 349W

CPU

105W

GPU

170W

Other

74W