Tools
PSU wattage calculator
Not sure your power supply can handle a new GPU? Pick your graphics card and CPU, add the rest of the system (board, RAM, drives and fans are usually 50–100 W), and the calculator adds 20% headroom. GPU presets use NVIDIA's rated power and CPU presets use AMD's TDP. Pick Custom for anything not listed.
Other parts (board, RAM, drives, fans): about 50–100 W.
We recommend 20% headroom.
Parts sum
635 W
Sum + headroom
762 W
NVIDIA lists 850 W required system power for this GPU on the compare sheet, with a footnote that uses their example CPU. Use the larger of the two as a floor, then read the PSU’s 12V rating, not only the label.
How the watts add
board = GPU + CPU + other
with headroom = board × (1 + headroom / 100)
TGP / TBP is the GPU package. TDP is the CPU’s published thermal design point. Neither is a measurement of your whole PC from the wall. NVIDIA also prints a required system power next to each 50-series card; that line uses their example CPU and is not this sum.
I run a desktop RTX 5080 (360 W TGP, 850 W system rec.) next to a 9950X3D2 (200 W TDP). The custom PC page is the cable and 12V-2x6 note, not this arithmetic.
Common questions
Where do the PSU calculator's wattage numbers come from?
GPU numbers come from NVIDIA's official specs, for example 360 W for the RTX 5080 with an 850 W recommended PSU. CPU numbers come from AMD's official TDPs, like 120 W for the 9800X3D.
Do I need 20% PSU headroom?
It's recommended, not required. 20% is a common safety margin for power spikes, and you can adjust it; a quality PSU with the right GPU cable matters just as much.
Should I use NVIDIA's recommended PSU or this calculator's result?
Use whichever is higher. NVIDIA's number assumes their own example system, while this calculator adds up your actual parts plus headroom.
Why is my CPU or GPU not in the PSU calculator?
Only parts with official wattage numbers are listed. Choose Custom and enter the TDP or TGP from the manufacturer's spec page.
Does the PSU calculator recommend a brand?
No. It only calculates wattage, so look for a quality PSU with a strong 12 V rail and the power connector your GPU needs.
Cooling around those watts is PC cooling. The chip pages sit on the PC build guides.