Picking a power supply (PSU) is where many first-time PC builders guess. Here is the simple method behind most PSU calculators, so you can check any build in a minute.
The 4-step formula
- GPU board power: for example RTX 4060 = 115 W, RTX 4070 = 200 W, RX 7800 XT = 263 W.
- CPU gaming power: 65 W chips usually draw 60-90 W in games; high-end K/X chips can pass 150 W.
- Everything else: add about 50-75 W for the motherboard, RAM, SSDs and fans.
- Headroom: multiply by 1.3-1.4 so the PSU runs in its efficient middle range and handles short power spikes.
Worked example
RTX 4060 + Ryzen 5 7600: 115 + 90 + 60 = ~265 W. x 1.4 = ~370 W.
A good 550 W unit is plenty, and leaves room for a GPU upgrade later.
Quality beats watts
A solid 550 W unit from a known brand is better than a cheap 750 W unit. Check for 80 Plus Bronze or better, a decent warranty, and the PCIe power connectors your card needs.
Want the math done for you?
I built a free PSU calculator at TechVerio that does these steps for any CPU and GPU pair.
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