Computer Power Calculator

Intel figures are Maximum Turbo Power (the peak, not Processor Base Power). AMD lists only Default TDP; its socket power limit (PPT) is higher, so treat AMD presets as a lower bound or enter PPT as a custom value.
Used only when the processor is set to Custom. Enter Intel Maximum Turbo Power or AMD PPT.
Whole-board figures: NVIDIA Total Graphics Power or AMD Typical Board Power. Factory-overclocked partner cards may draw more; use Custom for those.
Used only when the graphics card is set to Custom.
Used only when the graphics card is set to Custom. NVIDIA "Required System Power" or AMD "Minimum PSU Recommendation"; 0 if the maker publishes none.
No board maker publishes this. Seasonic allows 20-60 W; 40 W is a design-choice default inside that range.
Crucial rule of about 3 W per 8 GB (stated for DDR3/DDR4): 6 W for a 16 GB DIMM, 12 W for 32 GB. Seasonic allows 8-15 W for 32 GB of DDR5 in total.
Samsung 990 PRO active average read: 5.5 W (1 TB), 6.1 W (2 TB), 6.5 W (4 TB).
Seagate BarraCuda ST2000DM008 operating typical 5.1 W. Spin-up (2.0 A at 12 V = 24 W per drive for a few seconds) is not in the sum.
Noctua NF-A12x25 PWM maximum input power 1.68 W (0.14 A x 12 V). Convert fans quoted in amps with A x 12 = W.
Arctic Liquid Freezer II 360 pump and VRM fan: 0.5-2.7 W. Seasonic allows 3-10 W. Enter 0 for an air cooler.
Enter the actual draw of bus-powered devices; keyboards and mice draw well under a port's limit.
Seasonic: at least 20-30 % for power spikes or overclocking; 25-30 % for sustained rendering or AI loads; 30-40 % for continuous compute. 20 % is a design-choice default.
Efficiency never changes the DC wattage you need; it sets how much the wall supplies and how much becomes heat.
The table cell used as eta. No interpolation is done between columns; the 50 % column is the design-choice default.
Recommended PSU rating
750 W
PSU Wattage Calculator
Component peak sum (DC)
550.24 W
Target with headroom
660.288 W
Next standard size above the target
750 W
GPU maker minimum PSU
750 W
PSU load at the component sum
73.37 %
80 PLUS efficiency used
90 %
AC wall draw at that efficiency
611.38 W
Heat lost in the PSU
61.14 W
ATX 3.x excursion budget, 100 microseconds
1,500 W
ATX 3.x excursion budget, 1 millisecond
1,350 W
ATX 3.x excursion budget, 10 milliseconds
1,200 W
ATX 3.x excursion budget, 100 milliseconds
900 W
Cross-check: Corsair GPU + CPU + 150 + 150 rule
850 W
How the size was reached
Next standard size above 660.288 W is 750 W, which also meets the graphics card maker's minimum of 750 W.
Worked out from NVIDIA GeForce RTX 50-series specification pages (Total Graphics Power, Required System Power) and 8 other sources.
The 20 % headroom, the standard size list, and the 40 W motherboard and 2.7 W pump defaults are design choices within published PSU-maker ranges, not standards constants.
Transient spikes are what the headroom covers; ATX 3.x units above 450 W must ride through 200 % of rated power for 100 microseconds, so do not add the excursion percentages on top of the sum again.
The graphics card maker's minimum PSU assumes a specific test system (NVIDIA: a Ryzen 9 9950X); a lower-power CPU does not permit going below it. Prefer an ATX 3.0/3.1 unit with a native 12V-2x6 cable for any 12V-2x6 card.

How this is worked out

7 steps
  1. Component peak sum = CPU 181 + GPU 304 + motherboard 40 + RAM 2 x 6 = 12 + SSD 1 x 5.5 = 5.5 + HDD 0 x 5.1 = 0 + fans 3 x 1.68 = 5.04 + pump 2.7 + USB 0 = 550.24 W DC
  2. Target = 550.24 x (1 + 20/100) = 660.288 W
  3. Smallest standard size >= 660.288 W is 750 W; recommended = max(750, vendor minimum 750) = 750 W
  4. PSU load at the component sum = 550.24 / 750 = 73.37 %
  5. AC wall draw = 550.24 / 0.9 (80 PLUS Gold, 115 V, 50 % column) = 611.38 W; heat = 61.14 W
  6. ATX 3.x excursion budget (Table 3-3, >450 W with 12V-2x6) = 750 W x 2 / 1.8 / 1.6 / 1.2 for 100 us / 1 ms / 10 ms / 100 ms
  7. Cross-check (Corsair rule): 304 + 181 + 150 + 150 = 785 W -> 850 W

Results are general information, not financial, tax, legal, medical or engineering advice.