EVGA SuperNOVA 1600 P2 Power Supply Review

Load Regulation, Hold-Up Time And Inrush Current

Test Setup

All measurements are performed using two Chroma 6314A mainframes equipped with the following electronic loads: six 63123A (350W each), one 63102A (100W x2) and one 63101A (200W). The aforementioned equipment is able to deliver 2500W of load, and all loads are controlled by custom-made software (Faganas ATE). We also use a Rigol DS2072A oscilloscope, a Picoscope 3424 oscilloscope, a Picotech TC-08 thermocouple data logger, two Fluke multimeters (289 and 175), a Keithley 2015 THD 6.5-digit bench DMM and a Yokogawa WT210 power meter. In addition, we include a wooden box, which, along with some heating elements, we used as a hot box. Moreover, we have at our disposal three more oscilloscopes (Rigol VS5042, Stingray DS1M12 and a second Picoscope 3424) and a Class 1 Brüel & Kjær 2250-L G4  Sound Analyzer, which is equipped with a type 4189 microphone that features a 16.6-140 dB(A)-weighted dynamic range. Finally, the latest addition in our testing gear is a FLIR E4 infrared camera, which, through some firmware modifications (many thanks to the fine folks at EEVblog's forums for this) is now able to deliver 320x240 resolution.

We conduct all of our tests at 40 °C to 45 °C ambient temperature to more accurately simulate the environment seen inside a typical system, with the range being derived from a standard ambient assumption of 23 °C, and 17 to 22 °C added for the typical temperature rise within a system.

Primary Rails Load Regulation And 5VSB Regulation

The following charts show the voltage values of the main rails, recorded over a range from 60W to the maximum specified load, and the deviation (in percent) for the same load range. The last two charts show how the 5VSB rail deals with the load we throw at it.

Hold-Up Time

Hold-up time is an important PSU characteristic; it represents the amount of time, usually measured in milliseconds, that a PSU can maintain output regulations as defined by the ATX spec without input power. In other words, it is the amount of time the system can continue to run without shutting down or rebooting during a power interruption. The ATX specification sets the minimum hold-up time to 16ms with the maximum continuous output load.

In the following screenshot, the blue line is the mains signal and the yellow line is the "Power Good" signal. The latter is de-asserted to a low state when any of the +12V, 5V or 3.3V output voltages fall below the under-voltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.

Strangely enough, the hold-up time of the 1600 P2 is significantly lower than the almost identical 1600 G2. Maybe in an effort to increase efficiency, EVGA had to make some changes that dropped the hold-up time below the ATX specification's 16ms.

Inrush Current

Inrush current or switch-on surge refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. Because of the APFC capacitor's charging current, PSUs produce large inrush current right as they are turned on. This can trip circuit breakers and fuses, and may also damage switches, relays and bridge rectifiers. As a result, the lower the inrush current of a PSU right as it is turned on, the better.

Naturally, the inrush current with 115V input is significantly lower than 230V.

The inrush current of the 1600 P2 with 230V is among the highest we have ever measured. That doesn't place it very far from the rest of the pack, though.

Load Regulation and Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 percent to 105 percent of the maximum load the supply can handle, in increments of 10 percentage points.

We conducted two additional tests. In the first metric, we stressed the two minor rails (5V and 3.3V) with a high load while the load at +12V was only 0.10 A. This test reveals whether the PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle while the load on the minor rails was minimal. 

The SuperNOVA 1600 G2 registers tighter voltage regulation on all rails. Apparently, in its effort to increase efficiency, Super Flower decided to decrease the load regulation performance a little bit. However, the 1600 P2 still exhibits excellent performance in this area. As you can see from the efficiency readings on the table above, Super Flower's approach allows for high efficiency throughout all load ranges, and the 1600 P2 successfully passes the strict 80 PLUS Platinum requirement.

In addition, despite the high ambient temperature inside our hot box, the power supply finishes the three initial tests without engaging its fan, thus keeping the output noise level at zero. Although we pushed the PSU hard, we still had to exceed 46 °C ambient in order to make the fan spin up. Up to a point, we were afraid that the fan circuit was broken since we expected much higher RPMs at such aggressive loads and operating temperatures. Super Flower must be incredibly confident about this platform's heat tolerance, since the fan increased its speed to >1500 RPM only when the PSU reached 1440W load and above. In addition, the large temperature delta difference between the PSU's intake and exhaust made quite an impression on us. We rarely see an exhaust temperature reaching 75 °C.