What PSU for a NVIDIA GeForce RTX 4090 and Core i9-14900K?
Pairing a NVIDIA GeForce RTX 4090 (450 W board power) with a Core i9-14900K (253 W peak) gives a system load of about 820 W. Both figures are verified against the manufacturers’ own specifications — the sources are linked below. Everything on this page applies equally to the Core i7-14700K, which has the same 253 W peak power — the load, the recommended supply and the cabling are identical, so there is no separate page for it.
Recommendations are planning estimates, not electrical or purchasing advice. The hardware figures behind them are vendor-published; your exact board-partner model and build can still differ.
Recommended PSU
1200 W
Leaves the supply at about 68% load under gaming.
Minimum
1000 W
Smallest quality tier we would pair with this build.
System load
820 W
450 W GPU + 253 W CPU + 117 W rest of build.
GPU power connector
1× 16-pin 12V-2x6
Plus the board’s EPS 12V cable for the CPU.
Where the power goes
Load is split fairly evenly — the NVIDIA GeForce RTX 4090 takes 55% of the 820 W total and the Core i9-14900K 31%. Both parts matter to the sizing, which is why the pairing is worth looking at rather than either part alone. The remaining 117 W covers the board, memory, one SSD, three fans and a USB allowance.
GPU 55% · CPU 31% · rest of build 14%
Why 1200 W
This is a close call. With standard headroom the requirement lands only about 3% above a 1000 W unit, so a high-quality 1000 W supply is not absurd — it would simply run closer to its limit, at roughly 82% load under gaming. We still recommend 1200 W: the margin buys quieter fan behaviour and room for the brief peaks a card of this class produces.
Graphics-card draw is not flat — brief peaks above the rated board power are normal, and a supply running close to its limit can trip on one. We do not publish a peak figure for the NVIDIA GeForce RTX 4090 because the manufacturer does not publish one. At 450 W this is firmly in the class where an ATX 3.1 (or 3.0) unit is worth insisting on: the specification requires supplies to ride out short excursions well above their continuous rating, and such units ship the native 12V-2x6 cable this card wants.
The card's manufacturer recommends 850 W for the NVIDIA GeForce RTX 4090 on its own. Paired with the Core i9-14900K, which can pull 253 W by itself, we arrive at 1200 W — 350 W higher. Vendor guidance assumes a mainstream companion CPU; this pairing is not that. The vendor figure is not wrong, it is answering a different question.
Cabling this build
The NVIDIA GeForce RTX 4090 takes 1× 16-pin 12V-2x6. Use the native 12V-2x6 cable that comes with an ATX 3.x supply rather than an adapter bundle, seat it until it clicks, and keep sharp bends away from the plug — a partially seated 16-pin connector is the known failure mode at this power level. On top of that the board needs its EPS 12V CPU cable — one 8-pin is enough for the Core i9-14900K at 253 W, though many boards expose a second socket you can leave empty.
Different case, more drives, or an AIO? Open the PSU Calculator with both parts pre-selected →
Figures above assume an ATX board, 2 RAM sticks, 1 SSD, 3 fans and a USB allowance, at the standard headroom profile.
Frequently asked questions
What PSU do you need for a NVIDIA GeForce RTX 4090 and Core i9-14900K?
We recommend a quality 1200 W power supply. The pairing draws about 820 W under load — 450 W for the card, 253 W for the CPU and 117 W for the rest of a typical build — and 1000 W is the smallest tier we would pair with it.
How much power does a NVIDIA GeForce RTX 4090 and Core i9-14900K build use?
About 820 W under a combined gaming load, which is roughly 68% of the 1200 W supply we recommend. That is a conservative figure built from vendor-published ceilings, so day-to-day draw is usually lower.
Is 850 W enough for a NVIDIA GeForce RTX 4090 and Core i9-14900K?
850 W is the card maker's recommendation for the NVIDIA GeForce RTX 4090 alone. With the Core i9-14900K in the same build we would step up to 1200 W, because that CPU can add 253 W on its own.
Does this apply to the Core i7-14700K as well?
Yes. The Core i7-14700K has the same 253 W peak power as the Core i9-14900K, so the load, the recommended supply and the cabling are all identical for that pairing.