Efficiency

Using the efficiency results from the previous page, we plotted a chart that shows the RM1000i's efficiency at low loads and loads equal to 20% -100% of the PSU's maximum-rated load.



The difference in efficiency between the RM1000 and RM1000i is very low with normal loads, although slightly in favor of the RM1000i. However, the older unit achieved a higher overall efficiency score with low loads, with the RM1000i following closely. Take a look at the graph for light loads and you will also notice that the Corsair HX1000i belonging to a higher category registered significantly lower efficiency than both RM units.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the RM1000i at loads much lower than 20% of its maximum-rated load (the lowest load the 80 Plus Standard measures). The loads we dial are 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.

The RM1000i performed very well at light loads; however, it didn't manage to beat out its predecessor's efficiency levels. With that said, the RM1000i's load regulation is much better than that of the RM1000, and its hold-up time is much longer, two factors that affect efficiency. Especially large bulk caps can affect efficiency, which has some manufacturers use bulk caps with less capacity than required to avoid losing a bunch of power on those caps. However, such an approach often leads to a lower hold-up time than the ATX spec specifies.

Corsair Link Screenshots

Screenshots of the Corsair Link software follow. The order of the screenshots is the same as the order of the tests shown in the table above (low loads efficiency test #1 to test #4).



The efficiency readings the Corsair Link software produced in the first three low-load tests were all significantly lower than those we measured with our lab-grade equipment. Accuracy picked up and was close to our readings in the last load test.

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.

While the 5VSB rail failed to impress us with its efficiency performance, its load regulation was amazing.

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and 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).

Phantom power was very low, barely exceeding 0.1 W, and energy consumption in standby will be even lower with 115 VAC input.

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 output noise follows. We measure the fan's noise from one 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 in an ambient of 38°C-45°C.



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



Strangely enough, passive mode didn't last very long in our cross load tests at normal ambient; however, the fan spun at low speeds most of the time. For a PSU capable of delivering 1 kW, output noise was very low with even high loads. The new RM1000i obviously falls in line with the RM units' tradition of operating quietly, and our measurements even show that it is quieter overall. High performance levels and a dead-silent operation are two components that are rather hard to combine, that's for sure, but Corsair managed to combine both with the RM1000i.

The following graph illustrates the fan's speed throughout the PSU's entire operating range. The ambient temperature was in-between 28°C and 30°C.



As you can see in the graph above, fan speed didn't exceed 1200 RPM at the worst of times.