KitGuru KitGuru.net – Tech News | Hardware News | Hardware Reviews | IOS | Mobile | Gaming | Graphics Cards
Additional technical assistance: Peter McFarland and Jeremy Price.
Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Over the coming months this configuration is likely to be adjusted further and fine tuned. We have changed our temperature settings today – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c in our environment to greater reflect warmer internal chassis conditions.
We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA
|
DC Output Load Regulation
|
||||||||||
|
Combined DC Load |
+3.3V
|
+5V
|
+12V
|
+5VSB
|
-12V | |||||
|
A
|
V
|
A
|
V
|
A
|
V
|
A
|
V
|
A | V | |
|
215W
|
1.54
|
3.41
|
1.52
|
5.05
|
16
|
12.15
|
0.50
|
5.01
|
0.20 | -12.18 |
|
410W
|
3.11
|
3.40
|
3.04
|
5.04
|
31
|
12.12
|
1.00
|
5.00
|
0.20 | -12.15 |
|
620W
|
5.02
|
3.39
|
5.03
|
5.04
|
47
|
12.07
|
1.50
|
5.01
|
0.30 | -12.14 |
| 810W | 6.51 | 3.37 | 6.49 | 5.03 | 62 | 12.05 | 2.00 | 5.01 | 0.40 | -12.12 |
|
1020W
|
8.02
|
3.34
|
8.01
|
5.02
|
78.5
|
11.98
|
0.5
|
5.01
|
0.20 | -12.09 |
The Revolution 85+ has delivered a solid set of results throughout all the testing above across various loads. The +3.3V and 5V rails remained steady between +/-2% of the nominal voltage instead of the recommended +/-5% and the +12V rail held within +/- 2%.
| Enermax Revolution 85+ 1020W | Maximum Load |
| 1205W |
The PSU reached 1205W before shutting down gracefully. It was able to run around 1200W for a short time. The overcircuit protection circuitry works perfectly which is always good to report to a potential customer.
Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.
| Cross Load Testing | +3.3V | +5V | +12V | -12V | +5VSB | |||||
| A | V | A | V | A | V | A | V | A | V | |
| 760W | 1.0 | 3.31 | 1.0 | 5.02 | 65.0 | 12.02 | 0.2 | -12.11 | 0.50 | 5.03 |
| 165W | 15.0 | 3.29 | 18.0 | 5.01 | 2.0 | 11.98 | 0.2 | -12.02 | 0.50 | 5.01 |
The Enermax Revolution handled our cross loading test with only very minor fluctuation, well within the safe parameters of each rail.
We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.
ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.
|
ATX12V Ver 2.2 Noise/Ripple Tolerance
|
|
|
Output
|
Ripple (mV p-p)
|
|
+3.3V
|
50
|
|
+5V
|
50
|
|
+12V1
|
120
|
|
+12V2
|
120
|
|
-12V
|
120
|
|
+5VSB
|
50
|
Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the Enermax unit complied with the ATX standard.
| AC Ripple (mV p-p) | ||||
| DC Load | +3.3V | +5V | +12V | 5VSB |
| 215W | 5 | 10 | 15 | 5 |
| 410W | 10 | 10 | 20 | 10 |
| 620W | 15 | 15 | 30 | 10 |
| 810W | 25 | 15 | 40 | 15 |
| 1020W | 35 | 20 | 65 | 20 |
These are a good set of results for the Enermax Revolution 1020W unit, although we were surprised to see 65 mV on the +12V rail under full load. This is still well within safe parameters, but a quick check of our older Enermax showed +12V ripple around 35mV, considerably better than this new model at full load.
Ambient temperatures for this test are kept at 35c to mirror real world internal case temperatures.
|
Efficiency (%)
|
|
|
215W
|
90.7
|
|
410W
|
90.4
|
|
620W
|
90.2
|
|
810W
|
88.8
|
| 1020W | 87.1 |
Efficiency is very impressive holding at 90%+ efficiency, right up to 750W when it starts to drop to around 87% at 1020W output. Gold classification might have been possible if Enermax had sold it with a lower total output rating.
We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.
Today to test the Power Supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.
As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.
KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum
|
Noise (dBA)
|
|
|
215W
|
26.8
|
|
410W
|
28.1
|
|
620W
|
31.7
|
|
810W
|
33.7
|
| 1020W | 37.9 |
The noise levels are excellent as well, with it really only becoming audible at 800W+ output levels – not a situation many of us would be in on a regular basis. 33 dBa is still quite a low rating and the noise of the PSU at this level would be basically inaudible in conjunction with a couple of case fans.
|
Temperature (c)
|
||
| Intake | Exhaust | |
|
215W
|
35
|
36 |
|
410W
|
35
|
38 |
|
620W
|
40
|
45 |
|
810W
|
42
|
49 |
| 1020W | 46 | 55 |
The large Twister based fan combines a very potent combination of low noise levels with good cooling performance. Even in our warm 35c environment the exhaust temperature was only 9c higher than the intake.
|
Maximum load
|
Efficiency
|
|
1205W
|
84.7
|
We like to rate efficiency at the maximum output our supply can deliver before switching off, which is 84.7% in this case. Not a realistic set of conditions for anyone to be running, but interesting regardless.
