PSU Wattage Guide — How Much Power Do You Need?

PSU Wattage Guide

Choosing the right power supply is one of the most important decisions in a PC build. Too little wattage and your system will crash under load. Too much and you’re wasting money. This guide helps you calculate exactly what you need.

How to Calculate Your Power Requirements

Add up the Thermal Design Power (TDP) of your main components, then add 20–30% headroom for efficiency losses, transient spikes, and future upgrades.

Typical power draw by component:

CPU: 65W–253W (e.g. Ryzen 5 65W, Core i9 253W)
GPU: 115W–600W (e.g. RTX 4060 115W, RTX 4090 450W)
RAM (per stick): 3–5W
NVMe SSD (per drive): 5–10W
Case fans (each): 1–3W
Motherboard: 30–80W

Example: Ryzen 7 (105W) + RTX 4070 (200W) + RAM + storage + fans ≈ 380W total. Add 25% headroom = ~475W minimum. A 650W PSU is the sensible choice.

Recommended PSU Wattage by Build Type

Budget / Office build: 450–550W
Mid-range gaming (e.g. RTX 4060 Ti / RX 7700 XT): 650–750W
High-end gaming (e.g. RTX 4080 / RX 7900 XTX): 850–1000W
Flagship GPU (e.g. RTX 4090): 1000–1200W
Workstation / multi-GPU: 1200W+

Understanding 80 PLUS Efficiency Ratings

80 PLUS White: 80% efficiency. Entry level.
80 PLUS Bronze: 82–85% efficiency. Good budget choice.
80 PLUS Gold: 87–90% efficiency. Recommended for most builds.
80 PLUS Platinum: 90–92% efficiency. Excellent for high-wattage systems.
80 PLUS Titanium: 92–94% efficiency. Premium tier.

Modular vs Non-Modular

Non-modular: All cables permanently attached. Cheaper but harder to manage.
Semi-modular: Essential cables fixed; others detachable. Good balance.
Fully modular: All cables detachable. Best for cable management. Recommended.

Key Connector Types to Check

24-pin ATX: Main motherboard power — all PSUs include this.
4+4-pin EPS: CPU power. High-end boards may need two.
PCIe 6+2-pin / 16-pin (12VHPWR): GPU power. Check your PSU includes the correct cable for your GPU.
SATA power: For SATA SSDs and HDDs.