Efficiency

Using the efficiency results of the previous page, we plotted a chart showing the efficiency of the Venom 850 W at low loads and at loads equal to 20-110% of the PSU's maximum rated load.



See the text at the end of the previous page for a discussion of these results.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the Venom 850 W 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 500W of capacity). This is important for settings where the PC is in idle mode with power saving turned on.


Efficiency at low loads is not ground breaking, but is, to say the least, decent. With a 40 W load, the PSU manages to avoid readings below 70%, surpassing the 80% mark with an 80 W and a 100 W load. As you can see, the fan operates at low RPM with such low loads, even though the ambient during these tests was near the 40°C region.

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: three at 100, 250, and 1000 mA and one with the full load that the 5VSB rail can handle.


Efficiency at 5VSB is good enough since efficiency levels are, in all cases, close to the levels that the ATX spec recommends. However, we would like to see some higher readings, preferably close to the 80% mark, on the last two tests.

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).


Vampire power is below 0.5 W, which means the PSU meets the future and stricter ErP Lot 6 2013 directive by wasting less energy and reducing the carbon footprint. It will, in the long run, save you some money on your electricity bills.

Fan RPM & Delta Temperature

In the following chart illustrates the cooling fan's speed (RPMs) and the delta difference between input and output temperature. The following results were obtained at 40°C - 45°C ambient.