Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the Leadex-1000 at low loads and at loads equal to 20-110% of the PSU's maximum-rated load.



At low loads, efficiency is good for a 1 kW unit, but the Rosewill Tachyon 1000 W, based on the older SF Platinum platform, scores an even higher efficiency under the same conditions. Even the EVGA SuperNOVA unit using the same platform with a lower efficiency rating managed to take the lead from its Platinum sibling. We could state that the Platinum Leadex's platform aims for a higher efficiency at normal and higher loads, but the second graph shows that the differences there are minimal. So, you will already have begun to wonder what actual improvements the new platform offers. Well, there are the tighter voltage regulation and the better ripple suppression, but the components and tuning needed for the above two demand, as it seems, some sacrifices to be made in efficiency.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the Leadex-1000 at loads much lower than 20% of its maximum-rated load (the lowest load that the 80 Plus Standard measures). The loads that we dialed were 40-, 60-, 80-, and 100 W (for PSUs with over 500 W of capacity). This is important for settings where the PC is in idle mode with Power Saving turned on.

At low loads, efficiency is surely high, but not as high as SF's previous Platinum platform. Even the lower efficiency EVGA SuperNOVA unit manages to pass on ahead, although it uses a less efficient version of the Leadex platform. This new design undoubtedly has a tighter voltage regulation, but we, while some efficiency is lost on the extra components needed for such a voltage regulation, still expected a smaller efficiency difference to the older platform with a load under 100 W.

Another strange thing was that both our power meters went crazy. Their AC watt readings registered large deviations at lower loads, although the DC load was at a stable level during each test. We were only able to take accurate AC watt readings to calculate efficiency because of our custom-made software controlling the Chromas, since it has the ability to calculate and show the average values of each parameter. We also noticed the same behavior in the EVGA SuperNOVA G2 1000 W unit based on the same platform. Units that utilize LLC converters usually exhibit such strange behavior at low loads, but the Leadex Platinum's AC watt deviations were significant or we wouldn't bring them up.

5VSB Efficiency

The ATX spec states that the 5VSB standby supply's efficiency should be as high as possible and recommends 50% or higher efficiency with 100 mA of load, 60% or higher with 250 mA of load, and 70% or higher with 1 A or more of load.

We will take four measurements: one at 100, 250, and 1000 mA each, and one with the full load that the 5VSB rail can handle.

The 5VSB rail is both weak and inefficient. It is no match to the other high performance rails equipping this unit. We are pretty sure that SF didn't make any changes to the 5VSB circuit, using the same one as on their older Platinum platform. In the future, we would like to see an improved version of this circuit.

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and the voltage values of all rails (except -12V) when the PSU is in idle mode (powered on but without any load on its rails) and the power consumption when the PSU is in standby mode (without any load at 5VSB).

The unit consumes very little power in standby mode and meets the requirements of the ErP Lot 6 2013 directive with flying colors.

Fan RPM, Delta Temperature and Output Noise

The cooling fan's speed (RPMs) and the delta difference between input and output temperature are illustrated in the following chart. The following results were obtained at 40-46°C ambient.



A chart that shows the cooling fan's speed (RPMs) and the output noise follows. We measure the fan's noise from 1 meter away and inside a small custom-made anechoic chamber whose internals are completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit). The background noise inside the anechoic chamber was below 30 dBA during testing and the results were obtained with the PSU operating at 40-46°C ambient.



The following graph illustrates the fan's output noise throughout the entire operating range of the PSU. The same conditions of the above graph apply to our measurements, but the ambient in this case was between 28°C and 30°C.



The PSU operates very quietly on a normal summer day in a hot Mediterranean country like Greece. With its semi-passive mode enabled, the fan rarely engages at up to 50% load, and noise is kept low at full load, especially for a 1 kW unit. Super Flower did well in this area, making the new Leadex units the PSUs noise-haters will want to buy.