What is a PSU? (Power Supply Unit)
The PSU converts wall power into the stable voltages your components need. It’s the most under-appreciated part of a PC — and a bad one can take everything else down with it.
Reading PSU specs
Wattage (650W, 750W, 850W) must cover your components with headroom — GPUs are the biggest draw. 80+ ratings (Bronze, Gold, Platinum) indicate efficiency and generally build quality. All our builds use branded PSUs with appropriate ratings — no generic units.
Sizing a PSU for a GPU upgrade
Check your graphics card’s power draw (TGP) first. As a guide, NVIDIA recommends around 550W for an RTX 4060, 650W for an RTX 4070 or 5070, 750W for an RTX 3080 or 5070 Ti, and 850W for an RTX 5080. Our RTX GPU comparison lists the power draw of every RTX card, and every one of our gaming PC builds ships with a branded PSU matched to its GPU.
Signs of a failing PSU
Random shutdowns or restarts under load, PC not turning on at all, clicking or burning smells, or crashes only when gaming. PSU faults mimic other problems, which is why proper diagnosis matters before replacing parts blindly — see our PC won’t turn on troubleshooting guide.