To give as clear and repeatable a picture of a given PSU’s abilities, we have not just tested at full load. Instead, demand load testing will be done at 20% intervals (i.e. 20%, 40%, 60%, 80%, 100%) with the 3.3/5/12v rails monitored and recorded via HWInfo64’s built-in logging feature and backstopped by manual checking with a clamp meter. Each step will be held at that power level for 20 minutes per run and will be repeated 4 times, with an average “score” being the official record at said point. At each step noise of the included PSU’s fan will also be monitored via a professionally calibrated and NIST-certified DT-805 sound meter that is placed 24 inches away from it, with said results manually recorded.
Unless otherwise noted, or the PSU is intended for server environments, all testing will be done with an ambient room temperature of 25 Celsius (+/- 0.5c °C). While a touch on the high side, modern systems do tend to heat up their environment to some extent, thus this is a tougher than typical ambient test environment, but certainly not a ‘hot box’ one either. Thus, realistic while still not being overly easy on the PSU.
As we are using a percentage and not a specific wattage for each step, total power will vary from PSU to PSU based on the rated capacity of said test item. However, each step will be heavily weighted towards GPU and CPU loading, as few will ever run enough HDDs (and fans) to matter all that much.
When possible for the 20 percent and 40 percent, either a 65-watt Core Ultra 5 245 (manually set to 45-watt TDP) or a Core Ultra 7 265 will be used with either a low TDP Intel Battle Mage, NVIDIA xx50, xx60, or xx60Ti class card.
When possible, at higher steps, an AMD RYZEN 9 9950X at either stock or overclocked will be used, with proceeding higher TDP video cards starting with xx70-class and going up from there to xx90-class cards.
If additional power demand is required, the ‘9950X will be substituted for at first, a stock Intel Core i9-10980XE, and then said processor highly overclocked, where it will be consuming ~500 watts of power all on its own. If that is not enough to fully max out the wattage, said additional wattage demand will be fulfilled by daisy-chained (via molex or SATA adapters) 12v fans and/or the use of even more GPUS, etc. etc… until the PSU is overloaded and the OCP/OPP kicks in. At which point the number of 12v fans will be reduced until said protection does not shut the system down. Upon OS startup finalization, the actual wattage being handled will be recorded. At which point further reduction(s) will occur until it is at its rated 100 percent maximum output.
Main power draw will be recorded manually via the use of a wall plug power meter & monitor (“KillaWatt”) and confirmed via a clamp meter. The voltage of said mains power will also be recorded manually and noted in the charts so as to ensure accurate efficiency calculations.
