CalcuGrid

What PSU do I need for a Core i9-13900K?

550 W to 1200 W, depending on the graphics card beside it. With a GeForce RTX 4070 the answer is 650 W.

Where the watts go — Core i9-13900K with GeForce RTX 4070

Power draw by component for a Core i9-13900K build
Component Power
Core i9-13900K at its ceiling 253 W
GeForce RTX 4070 board power 200 W
Motherboard 25 W
Memory module x2 6 W
NVMe SSD 7 W
Case fan x3 6 W
Continuous draw 497 W

The recommendation of 650 W sits that draw at 76% of the supply's rating. The target is 80%: supplies lose capacity as they age, and a graphics card's millisecond transients have to come from somewhere.

Why the answer is a range

A Core i9-13900K is sold as a 125 W processor and draws 253 W when it boosts. Intel calls the second figure Maximum Turbo Power, and it is what the chip pulls whenever it turbos. Sizing a supply against the 125 W on the box is short by 128 W — 102% — before the graphics card is counted at all.

With a GeForce RTX 4070 the system draws 497 W at full tilt, which calls for 650 W. Across the 34 cards below the answer ranges from 550 W to 1200 W: with this processor it is the graphics card that moves the number, not the other way round.

What the box would have told you

Size a supply against the 125 W on this processor's box and, paired with GeForce RTX 5090, you would buy 1000 W. That build draws 872 W at full tilt — 87% of the unit you just bought, with nothing left for ageing or for the card's transients. It needs 1200 W.

That is not a quirk of this pairing. On all 34 cards here, sizing from the stated TDP lands you a smaller supply than the build calls for — by as much as 200 W at the top end.

Supply sized from the Core i9-13900K TDP against what the build needs
Graphics card Sized on TDP Actually needed Short by
RTX 5090 1000 W 1200 W +200 W
RTX 4090 800 W 1000 W +200 W
RTX 3090 Ti 800 W 1000 W +200 W
RTX 3090 650 W 850 W +200 W
RTX 3080 Ti 650 W 850 W +200 W

Core i9-13900K with every graphics card

Power supply needed for a Core i9-13900K with each graphics card
Graphics card System draw PSU needed Set by
GeForce RTX 5090 872 W 1200 W This build
GeForce RTX 4090 747 W 1000 W This build
GeForce RTX 3090 Ti 747 W 1000 W This build
GeForce RTX 5080 657 W 850 W Both agree
Radeon RX 7900 XTX 652 W 850 W This build
GeForce RTX 3090 647 W 850 W This build
GeForce RTX 3080 Ti 647 W 850 W This build
GeForce RTX 3080 647 W 850 W This build
GeForce RTX 4080 SUPER 617 W 800 W This build
GeForce RTX 4080 617 W 800 W This build
Radeon RX 7900 XT 612 W 800 W This build
Radeon RX 9070 XT 601 W 800 W This build
GeForce RTX 5070 Ti 597 W 750 W Both agree
GeForce RTX 3070 Ti 587 W 750 W This build
GeForce RTX 4070 Ti SUPER 582 W 750 W This build
GeForce RTX 4070 Ti 582 W 750 W This build
Radeon RX 7800 XT 560 W 700 W Both agree
Radeon RX 7900 GRE 557 W 700 W Both agree
GeForce RTX 5070 547 W 700 W This build
Radeon RX 7700 XT 542 W 700 W Both agree
GeForce RTX 4070 SUPER 517 W 650 W Both agree
GeForce RTX 3070 517 W 650 W Both agree
Radeon RX 9070 517 W 650 W Both agree
GeForce RTX 4070 497 W 650 W Both agree
GeForce RTX 3060 Ti 497 W 650 W This build
GeForce RTX 5060 Ti 477 W 600 W Both agree
GeForce RTX 3060 467 W 600 W This build
GeForce RTX 4060 Ti 462 W 600 W This build
Radeon RX 7600 462 W 600 W This build
Radeon RX 9060 XT 457 W 600 W This build
GeForce RTX 5060 442 W 600 W This build
GeForce RTX 5050 427 W 550 W Both agree
GeForce RTX 3050 427 W 550 W Both agree
GeForce RTX 4060 412 W 550 W Both agree

Frequently asked questions

What PSU do I need for a Core i9-13900K?
It depends entirely on the graphics card: 550 W with the lightest here, 1200 W with the heaviest. Paired with a GeForce RTX 4070 the answer is 650 W.
How many watts does a Core i9-13900K actually draw?
253 W at its ceiling, not the 125 W on the spec sheet. Intel publishes the higher number as Maximum Turbo Power; the lower one is a thermal design target, and the gap between them is 128 W.
Is the 125 W TDP the number to size a PSU against?
No. TDP describes what the cooler has to remove under a sustained load, not what the socket can pull in the moment it boosts. Using it here would leave you 128 W short.
Does a Core i9-13900K need a bigger PSU than its TDP suggests?
Yes — 128 W more, before the graphics card. That is the difference between a supply that copes and one that trips under a load spike.
What happens if I size my PSU from the 125 W TDP?
You would buy a supply that is too small on 34 of the 34 cards here, by as much as 200 W — often a whole size, sometimes two.

A sizing estimate, not a measurement. It adds the processor's power ceiling, the graphics card's rated board power and an itemised allowance for the rest of the system, then leaves headroom so the supply is not running at its limit. Real draw depends on the board's power profile, how far the parts are overclocked, and how a particular graphics card handles transient spikes. Treat a result within 50 W of a supply's rating as a reason to choose the next size up.

Data on this page last verified .

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