What Size Power Supply Do I Need? (Simple PSU Sizing)

Too small and your PC shuts off mid-game. Too big and you wasted money. Here's how to get it right in 30 seconds.

The quick formula

Add your GPU's gaming power + your CPU's + about 80W for everything else, multiply by 1.3, and round up to the next common size (650, 750, 850, 1000W). If the graphics card maker publishes a recommended PSU size, use whichever number is higher. The headroom covers short power spikes. This is the same math the PC Atlas compatibility checker uses.

Typical sizes

• RX 9060 XT / RTX 5060 / Arc B580 + 6–8 core CPU: 550–650W.
• RTX 5070 / RX 9070 + Ryzen 7 / X3D: 650–750W.
• RX 9070 XT / RTX 5070 Ti: 750W (MSI recommends 750W for a 5070 Ti gaming build, 850W with an overclocked Ryzen 7 / X3D).
• RTX 5080: 850W. RTX 5090: 1000W or more.

What to look for

• ATX 3.1 for any modern GPU. It's built to handle GPU power spikes.
• A native 12V-2x6 cable for NVIDIA RTX 50 cards, plugged in fully. Avoid adapters where you can.
• 80 Plus Gold from a known brand (Corsair, Seasonic, MSI, Montech Century, be quiet!). Skip unbranded units.
• Never buy a power supply used. A failing PSU can take other parts with it.

The PC Atlas Wizard adds up your parts' power draw and picks a PSU with headroom automatically.