: Spending extra money on a 1200W PSU for a system that only draws 400W cuts into your GPU or CPU budget.
: PSUs operate at peak efficiency between 40% and 80% load. Running a high-wattage PSU at 15% load wastes electricity. Key Hardware Components That Consume the Most Power
Mechanical Hard Disk Drives (HDDs) require 6W to 10W during spin-up.
Calculators typically use the following breakdown of component power consumption: