Computing 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.
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
450 W
PSU Wattage Calculator
Component peak sum (DC)
246.24 W
Target with headroom
295.488 W
Next standard size above the target
450 W
GPU maker minimum PSU
0 W
PSU load at the component sum
54.72 %
80 PLUS efficiency used
90 %
AC wall draw at that efficiency
273.60 W
Heat lost in the PSU
27.36 W
ATX 3.x excursion budget, 100 microseconds
675 W
ATX 3.x excursion budget, 1 millisecond
653 W
ATX 3.x excursion budget, 10 milliseconds
608 W
ATX 3.x excursion budget, 100 milliseconds
495 W
Cross-check: Corsair GPU + CPU + 150 + 150 rule
550 W
How the size was reached
Next standard size above 295.488 W is 450 W, which also meets the graphics card maker's minimum of 0 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.

How this is worked out

7 steps
  1. Component peak sum = CPU 181 + GPU 0 + 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 = 246.24 W DC
  2. Target = 246.24 x (1 + 20/100) = 295.488 W
  3. Smallest standard size >= 295.488 W is 450 W; recommended = max(450, vendor minimum 0) = 450 W
  4. PSU load at the component sum = 246.24 / 450 = 54.72 %
  5. AC wall draw = 246.24 / 0.9 (80 PLUS Gold, 115 V, 50 % column) = 273.6 W; heat = 27.36 W
  6. ATX 3.x excursion budget (Table 3-3, <=450 W) = 450 W x 1.5 / 1.45 / 1.35 / 1.1 for 100 us / 1 ms / 10 ms / 100 ms
  7. Cross-check (Corsair rule): 0 + 181 + 150 + 150 = 481 W -> 550 W

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