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Primary Rails And 5VSB Load Regulation
The following charts show the main rails' voltage values recorded between a range of 40W up to the PSU's maximum specified load, along with the deviation (in percent). Tight regulation is an important consideration every time we review a power supply because it facilitates constant voltage levels despite varying loads. Tight load regulation also, among other factors, improves the system’s stability, especially under overclocked conditions and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.
The load regulation is tight on all rails.
Hold-Up Time
Put simply; hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption.
Results 9-12: Hold-Up Time
The hold-up time exceeds 17ms and the power ok signal is accurate, so no problems here.
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. A large enough inrush current can cause circuit breakers and fuses to trip. It can 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.
Results 13-14: Inrush Current
The inrush current readings are at normal levels, given the PSU's capacity. There are other similar capacity units, though, we notably lower inrush current readings.
10-110% Load Tests
These tests reveal the PSU's load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.
Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | Temps (In/Out) | PF/AC Volts |
1 | 6.922A | 1.980A | 1.996A | 0.993A | 105.043 | 86.758% | 0 | <6.0 | 44.55°C | 0.952 |
12.053V | 5.053V | 3.308V | 5.039V | 121.076 | 39.53°C | 115.14V | ||||
2 | 14.831A | 2.973A | 2.996A | 1.192A | 209.542 | 90.064% | 1378 | 38.7 | 40.37°C | 0.988 |
12.044V | 5.051V | 3.304V | 5.035V | 232.659 | 45.86°C | 115.13V | ||||
3 | 23.143A | 3.469A | 3.485A | 1.393A | 314.635 | 91.676% | 0 | <6.0 | 47.10°C | 0.995 |
12.039V | 5.047V | 3.301V | 5.028V | 343.203 | 41.24°C | 115.13V | ||||
4 | 31.462A | 3.966A | 4.003A | 1.593A | 419.857 | 91.624% | 1376 | 38.6 | 41.39°C | 0.997 |
12.035V | 5.045V | 3.298V | 5.023V | 458.241 | 48.50°C | 115.12V | ||||
5 | 39.442A | 4.962A | 5.008A | 1.794A | 525.162 | 91.776% | 1162 | 34.0 | 42.00°C | 0.997 |
12.034V | 5.041V | 3.295V | 5.018V | 572.220 | 49.83°C | 115.12V | ||||
6 | 47.376A | 5.959A | 6.019A | 1.996A | 629.721 | 91.574% | 1185 | 34.5 | 42.89°C | 0.997 |
12.029V | 5.038V | 3.291V | 5.013V | 687.665 | 51.76°C | 115.12V | ||||
7 | 55.414A | 6.955A | 7.026A | 2.197A | 735.032 | 90.848% | 1388 | 38.8 | 43.08°C | 0.997 |
12.017V | 5.035V | 3.288V | 5.008V | 809.081 | 52.23°C | 115.12V | ||||
8 | 63.441A | 7.954A | 8.038A | 2.400A | 840.292 | 90.257% | 1389 | 38.9 | 43.64°C | 0.998 |
12.009V | 5.031V | 3.285V | 5.003V | 930.996 | 53.43°C | 115.11V | ||||
9 | 71.854A | 8.454A | 8.530A | 2.400A | 945.211 | 89.799% | 1394 | 39.2 | 44.90°C | 0.998 |
12.006V | 5.030V | 3.283V | 5.002V | 1052.580 | 55.84°C | 115.10V | ||||
10 | 80.026A | 8.957A | 9.055A | 3.008A | 1050.046 | 89.184% | 1397 | 39.2 | 45.89°C | 0.998 |
12.000V | 5.027V | 3.280V | 4.989V | 1177.396 | 57.80°C | 115.10V | ||||
11 | 88.806A | 8.958A | 9.061A | 3.009A | 1154.869 | 88.620% | 1398 | 39.2 | 46.57°C | 0.998 |
11.994V | 5.026V | 3.278V | 4.987V | 1303.175 | 58.90°C | 115.09V | ||||
CL1 | 0.158A | 14.006A | 14.000A | 0.000A | 118.594 | 81.352% | 1375 | 38.6 | 42.04°C | 0.901 |
12.042V | 5.036V | 3.297V | 5.077V | 145.779 | 49.25°C | 115.14V | ||||
CL2 | 83.358A | 1.002A | 1.002A | 1.000A | 1014.497 | 89.861% | 1393 | 39.0 | 45.11°C | 0.998 |
12.010V | 5.042V | 3.289V | 5.019V | 1128.965 | 57.03°C | 115.10V |
The PSU can easily deliver full power under high operating temperatures, and the performance of the APFC converter is excellent since even with light loads, it achieves power factor readings that are close to unity. On the other hand, the fan speed profile is a mess, since it pushes the fan to spin at high speeds without this being necessary. Moreover, the lowest fan speed is set at 1162 RPM, which is pretty high.
20-80W Load Tests
In the following tests, we measure the PSU's efficiency at loads significantly lower than 10% of its maximum capacity (the lowest load the 80 PLUS standard measures). This is important for representing when a PC is idle with power-saving features turned on.
Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | PF/AC Volts |
1 | 1.210A | 0.496A | 0.486A | 0.198A | 19.716 | 65.751% | 0 | <6.0 | 0.724 |
12.063V | 5.059V | 3.312V | 5.055V | 29.986 | 115.14V | ||||
2 | 2.471A | 0.991A | 0.998A | 0.396A | 40.126 | 78.276% | 0 | <6.0 | 0.809 |
12.064V | 5.057V | 3.311V | 5.051V | 51.262 | 115.14V | ||||
3 | 3.667A | 1.485A | 1.480A | 0.595A | 59.638 | 82.298% | 0 | <6.0 | 0.847 |
12.061V | 5.056V | 3.310V | 5.048V | 72.466 | 115.14V | ||||
4 | 4.930A | 1.981A | 1.995A | 0.793A | 80.054 | 83.549% | 1373 | 38.5 | 0.869 |
12.057V | 5.054V | 3.309V | 5.044V | 95.817 | 115.14V |
During the fourth test the fan's noise exceeds 38 dB(A), something unacceptable given the applied conditions and the PSU's high efficiency levels.
2% or 10W Load Test
Intel plans on raising the ante at efficiency levels under ultra-light loads. So from July 2020, the ATX spec will require 70% and higher efficiency with 115V input. The applied load is only 10W for PSUs with 500W and lower capacities, while for stronger units we dial 2% of their max-rated-capacity.
Test # | 12V | 5V | 3.3V | 5VSB | DC/AC (Watts) | Efficiency | Fan Speed (RPM) | PSU Noise (dB[A]) | PF/AC Volts |
1 | 1.564A | 0.270A | 0.272A | 0.056A | 21.418 | 67.051% | 0 | <6.0 | 0.741 |
12.064V | 5.058V | 3.311V | 5.057V | 31.943 | 115.14V |
The efficiency with 2% load exceeds 65%, so it is quite high, still is lower than 70%, though.
Efficiency
Next, we plotted a chart showing the PSU’s efficiency at low loads, and loads from 10 to 110% of its maximum-rated capacity. The higher a PSU’s efficiency, the less energy goes wasted, leading to a reduced carbon footprint and lower electricity bills.
The efficiency levels are satisfactory in all load ranges: super-light, light and normal.
5VSB Efficiency
Test # | 5VSB | DC/AC (Watts) | Efficiency | PF/AC Volts |
1 | 0.100A | 0.500 | 75.415% | 0.051 |
4.992V | 0.663 | 115.12V | ||
2 | 0.250A | 1.247 | 77.550% | 0.119 |
4.987V | 1.608 | 115.12V | ||
3 | 0.550A | 2.740 | 78.286% | 0.229 |
4.981V | 3.500 | 115.12V | ||
4 | 1.000A | 4.973 | 77.377% | 0.337 |
4.973V | 6.427 | 115.12V | ||
5 | 1.500A | 7.446 | 77.305% | 0.404 |
4.963V | 9.632 | 115.12V | ||
6 | 3.001A | 14.803 | 76.731% | 0.489 |
4.933V | 19.292 | 115.12V |
Results 19-20: 5VSB Efficiency
This is not the best 5VSB circuit that we have seen from CWT when it comes to efficiency, but you cannot call it bad, either.
Power Consumption In Idle And Standby
Mode | 12V | 5V | 3.3V | 5VSB | Watts | PF/AC Volts |
Idle | 12.075V | 5.054V | 3.309V | 5.054V | 6.328 | 0.381 |
115.2V | ||||||
Standby | 0.042 | 0.003 | ||||
115.2V |
Results 21-22: Vampire Power
The vampire power is low with both voltage inputs.
Fan RPM, Delta Temperature, And Output Noise
All results are obtained between an ambient temperature of 37 to 47 degrees Celsius (98.6 to 116.6 degrees Fahrenheit).
The fan profile is a complete mess. Thermaltake along with CWT should fix it as soon as possible.
The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.
Even under normal operating temperatures, the fan profile continues to trouble us. The fan spins at very high speeds at light and moderate loads, without an obvious reason. The transition between passive and active fan operation should be smoother.
MORE: Best Power Supplies
MORE: How We Test Power Supplies
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Current page: Load Regulation, Hold-Up Time, Inrush Current, Efficiency and Noise
Prev Page Specifications and Part Analysis Next Page Protection Features, DC Power Sequencing, Cross-Load Tests and Infrared ImagesAris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.
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