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Where the 427 W comes from
Gaming profile for this pair
Line
Watts
Why this figure
Ryzen 7 9800X3D
120 W
Default TDP 120 W, PPT 162 W
GeForce RTX 5070
250 W
Total Graphics Power 250 W
Motherboard allowance
35 W
Chipset, VRM overhead, and onboard devices.
Memory, 2× DDR5
10 W
Planning allowance per module.
NVMe, 1
6 W
Active-drive allowance.
Fans, 3
6 W
Case or radiator fans.
The vendor number, kept separate
Ryzen 7 9800X3D base power is 120 W and the package limit is 162 W (derived).GeForce RTX 5070 board power is 250 W.NVIDIA publishes a system minimum of 650 W. NVIDIA's required system power is a minimum for a PC configured with a Ryzen 9 9950X. NVIDIA recommends a PCIe CEM 5.1 compliant PSU. Power requirements can differ with the rest of the system.
WattWise's minimum for the gaming estimate is 550 W. The vendor figure is 100 W higher.Their number is a floor for the reference PC they named. It is not added on top of ours.
GeForce RTX 5070 is rated 250 W. 1× 300W or greater PCIe Gen 5 (12V-2x6) cable, or 2× 8-pin via the included adapter. The connector budget covers the rated board power.
Do not add a second copy of the board power for spikes. Intel ATX design guide 336521, updated for PCIe CEM 5.1, requires a PSU above 450 W with a 12V-2x6 connector to hold 200% of its label for 100 µs, 180% for 1 ms, 160% for 10 ms, and 120% for 100 ms, at the duty cycles in that table. A card above 75 W may reach 3× sustained power for 100 µs or less. Use a native 12V-2x6 cable rated at least 300 W and seat it fully. Sense pins advertise 150, 300, 450, or 600 W.
Power-limit ceiling for this exact pair: 469 W, minimum 600 W, efficiency size 1,000 W. That row is a combined render, not a typical game.