PSU Wattage Guide for Gaming PCs
The power supply is the part buyers ignore until a new GPU trips shutdowns. Here is how much wattage you need by tier, and what to verify on used rigs in Ontario.
Wattage targets by GPU tier
Size the PSU (power supply unit) for peak GPU draw plus CPU, drives, and fans, with roughly 20–30% headroom. Practical starting points for modern builds:
Entry 1080p (RTX 4060 class, RX 7600): quality 550–650 W. Mid 1440p (RTX 4070 / 5070, RX 7800 XT): 650–750 W. High 1440p–4K (RTX 4070 Ti Super, 5070 Ti, RX 7900 XTX): 750–850 W. Flagship (RTX 4080/4090 class): 850 W+ from a reputable brand. A 750 W name-brand unit beats a no-name “850 W” every time.
80 Plus ratings and why brand matters
80 Plus Bronze/Gold/Platinum labels efficiency at load, not build quality. Pair the rating with known OEM platforms: Seasonic, Corsair RM/RMx, be quiet!, Super Flower, and similar lines show up in reliable gaming rigs. Cheap PSUs fail quietly until they take other parts with them. On Ontario used listings, a missing PSU model is a negotiation point, not a minor detail.
Used PC checks before you upgrade the GPU
Read the sticker on the PSU side panel. Note wattage, brand, and whether cables are modular. If a seller swapped in a huge GPU but kept a 500 W office unit, expect crashes under load. Ask to run OCCT or a game benchmark while you watch; random reboots mean walk away. Full steps live in our used PC inspection checklist.
Upgrades and resale in Ontario
Planning an RTX 5070 Ti later? Buy headroom now so you are not replacing the PSU twice. Selling? State PSU brand and wattage in the title; buyers filtering for safe upgrade paths will pay more. Shopping complete systems? Browse inventory where PSU specs are listed, or message us if you want a build matched to your GPU pick and GPU tier.
Inspect power supplies using our used PC checklist and match GPU tier in the best value GPU guide.
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