What power supply do I need for the RTX 4090?

With a typical mid-range CPU the RTX 4090 needs about a 1000 W power supply (estimated load 670 W). With a 65 W-class CPU 850 W is enough; with a 250 W-class flagship CPU plan on 1200 W.

How much power does the RTX 4090 draw?

Rated board power is 450 W. Brief transient spikes can reach roughly 675 W, which is why we size the PSU with 30% headroom.

RTX 4090 power supply requirements: what PSU wattage do you need?

The NVIDIA GeForce RTX 4090 is rated at 450 W board power. Short transient spikes can reach about 675 W, so the power supply must have headroom beyond the sum of the parts. Here is what that means with three classes of processor.

CPU class	Example	Estimated load	Recommended PSU
65 W-class (e.g. Ryzen 5/7 non-X)	Ryzen 7 9700X	615 W	850 W
125–180 W-class (mid-range K / X)	Ryzen 7 9800X3D	670 W	1000 W
250 W-class (flagship Intel K)	Core i7-13700K	803 W	1200 W

How we calculate it

Estimated load = CPU maximum turbo power + 450 W for the card + 100 W for motherboard, memory, storage and fans. We multiply by 1.3 for transient headroom and round up to the next common PSU size. Full details on the methodology page.

Connectors

Cards in this power class use the 12V-2x6 (12VHPWR) connector or three 8-pin PCIe connectors depending on the board partner. Prefer an ATX 3.x power supply with a native 12V-2x6 cable over adapters.

When to step up a tier

Heavy overclocking, custom water cooling, more than four drives or a lot of RGB each add tens of watts. If two or more apply, buy the next size up. Efficiency and fan noise are also best at 50–70% load, which the 1.3× rule already lands you in.