Efficiency

Using the efficiency results from the previous page, we plotted a chart showing efficiency of the XTS-1000 at low loads and at loads equal to 20% -100% of the PSU's maximum-rated load.



The XTS-1000 easily took first place in our chart for light loads, and placed very well in our normal loads chart as there is only a very small gap to the top. This is definitely an incredibly efficient PSU, one of the best-performing Platinum units out there.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the XTS-1000 at loads much lower than 20% of its maximum-rated load (the lowest load the 80 Plus Standard measures). The loads we dialed were 40 W, 60 W, 80 W, 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.

Semi-passive mode shone with very light loads as it basically nullified output noise for as long as the unit had to deal with light tasks. However, as has been stated, semi-passive mode didn't last for very long in our test sessions with normal loads, so you had better be able to cope with noise if your intent is to make the most of this unit's capacity.

5VSB Efficiency

The ATX specification states that 5VSB standby supply 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 the 5VSB rail can handle.

It has been a while since we last saw a PSU crack the 80% mark on its 5VSB rail. Note that such efficiency levels aren't even easily achievable by modern 5VSB circuits. To provide you with an analogy: 80% efficiency at 5VSB with even the full load is about as tough to achieve as the 80 Plus Platinum certification for a PSU.

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).

As expected of a Platinum PSU, vampire power was below 0.2 W.

Fan RPM, Delta Temperature & 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 38°C-45°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, inside a small custom-made anechoic chamber whose internals are completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit). Background noise inside the anechoic chamber was below 20 dBA during testing, and the results were obtained with the PSU operating at 38°C-45°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 temperature was in-between 28°C and 30°C.



Passive mode lasts significantly longer under normal conditions, at least compared to our high ambient tests, and the PSU actually produces very little noise at up to 700-750 W; however, noise output increases dramatically afterward and even exceeds 50 dBA with the full load.