A bootable operating system, software (HWMonitor, HWiNFO64, or OCCT).
Digital multimeter (DMM) with 0.1mV resolution, paperclip for PSU jump start, PSU load (optional: resistor load bank or an old hard drive). how to check psu
One standard paperclip or a short length of wire (18-20 AWG), optional PSU jumper bridge tool. A bootable operating system