All measurements were performed using two Chroma 6314A mainframes equipped with the following electronic loads: six 63123A [350 W each], one 63102A [100 W x2], and one 63101A [200 W]. The aforementioned equipment is capable of delivering 2500 W of load, and all loads are controlled by a custom-made software. We also used a Rigol DS2072A oscilloscope kindly sponsored by Batronix, a Picoscope 3424 oscilloscope, a Picotech TC-08 thermocouple data logger, two Fluke multimeters (models 289 and 175), and a Yokogawa WT210 power meter. We also included a wooden box, which, along with some heating elements, was used as a hot box. Finally, we had at our disposal three more oscilloscopes (Rigol VS5042, Stingray DS1M12, and a second Picoscope 3424), and a CEM DT-8852 sound level meter. In this article, you will find more details about our equipment and the review methodology we follow. Finally, we conduct all of our tests at 40°C-45°C ambient to simulate the environment seen inside a typical system with a higher accuracy, with 40°C-45°C being derived from a standard ambient assumption of 23°C and 17°C-22°C being added for the typical temperature rise within a system.
Rigol DS2072A kindly provided by:
Primary Rails Voltage Regulation
The following charts show the voltage values of the main rails, recorded over a range from 60 W to the maximum specified load, and the deviation (in percent) for the same load range.
5VSB Regulation
The following chart shows how the 5VSB rail deals with the load we throw at it.
Hold-up Time
Hold-up time is a very important PSU characteristic and represents the amount of time, usually measured in milliseconds, 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 16 ms 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 undervoltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.
Hold-up time unfortunately didn't reach 16 ms, so the unit failed this test. Units with such a high capacity struggle to achieve the minimum allowed time the ATX spec sets as there is only so much room on the main PCB for large bulk caps.
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 charging current of the APFC capacitor(s), PSUs produce large inrush-current right as they are turned on. Large inrush current can cause the tripping of 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.
While it didn't reach the required hold-up time, its bulk caps are still huge, so its inrush current was also pretty high.
Voltage Regulation and Efficiency Measurements
The first set of tests revealed the stability of the voltage rails and the efficiency of the Leadex-1200. The applied load was equal to (approximately) 20%, 40%, 50%, 60%, 80%, 100% and 110% of the maximum load that the PSU can handle.
We conducted two additional tests. In the first test, 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 dialed the maximum load the +12V rail can handle while the load on the minor rails was minimal.
Voltage Regulation & Efficiency Testing Data - Super Flower SF-1200F-14MP
Test
12 V
5 V
3.3 V
5VSB
Power (DC/AC)
Efficiency
Fan Speed
Fan Noise
Temp (In/Out)
PF/AC Volts
20% Load
17.976A
1.982A
1.999A
0.996A
239.73W
92.00%
0 RPM
0 dBA
49.15°C
0.957
12.137V
5.028V
3.299V
5.003V
260.57W
36.99°C
230.2V
40% Load
36.365A
3.981A
4.006A
1.201A
479.61W
93.34%
1010 RPM
37.8 dBA
39.98°C
0.984
12.113V
5.020V
3.293V
4.984V
513.85W
45.20°C
230.1V
50% Load
45.440A
4.976A
5.014A
1.610A
599.53W
93.25%
1010 RPM
37.8 dBA
40.52°C
0.987
12.107V
5.017V
3.290V
4.967V
642.95W
46.13°C
230.0V
60% Load
54.546A
5.982A
6.024A
2.019A
719.45W
93.11%
1010 RPM
37.8 dBA
41.88°C
0.990
12.095V
5.013V
3.286V
4.948V
772.70W
47.97°C
230.0V
80% Load
72.989A
7.988A
8.051A
2.435A
959.25W
92.32%
1530 RPM
46.5 dBA
43.78°C
0.991
12.069V
5.005V
3.279V
4.923V
1039.00W
50.16°C
229.9V
100% Load
92.340A
9.005A
9.074A
2.545A
1199.16W
91.50%
1995 RPM
53.2 dBA
44.99°C
0.991
12.043V
4.999V
3.273V
4.905V
1310.55W
51.81°C
229.8V
110% Load
102.433A
9.009A
9.079A
2.550A
1319.12W
91.02%
1995 RPM
53.2 dBA
45.58°C
0.991
12.027V
4.994V
3.270V
4.899V
1449.30W
52.75°C
229.7V
Crossload 1
0.096A
12.005A
12.005A
0.004A
100.94W
82.32%
1530 RPM
46.5 dBA
44.07°C
0.690
12.155V
5.019V
3.289V
5.031V
122.62W
50.26°C
230.6V
Crossload 2
99.942A
1.002A
1.003A
1.001A
1215.97W
91.86%
1995 RPM
53.2 dBA
45.04°C
0.991
12.035V
5.005V
3.285V
4.957V
1323.80W
52.02°C
229.8V
Voltage regulation was within 1% for the three main rails (12V, 5V, and 3.3V), which is amazing as it is pretty hard to achieve such tight regulation for a 1.2 kW PSU. The big Leadex unit also didn't have a problem delivering 1320 W at over 45°C, and, as you can see in the table above, the fan only started its operation during the 40% load test to increase its speed in the 80% load test. The fan can be very noisy while the PSU is taxed heavily as it peaks at 2000 RPM, but pushing the Leadex-1200 W to its limit would be very hard in real life because its efficiency keeps its energy losses to a minimum, which would have the fan operate at very low RPM to take care of what little heat it produces.