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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. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) 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
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA
We are running all four 12V rails into one final test result (12v)
|
DC Output Load Regulation
|
||||||||||
|
Combined DC Load |
+3.3V
|
+5V
|
+12V
|
+5VSB
|
-12V | |||||
|
A
|
V
|
A
|
V
|
A
|
V
|
A
|
V
|
A | V | |
|
100W
|
1.58
|
3.34
|
1.79
|
5.05
|
6.63
|
12.12
|
0.50
|
5.05
|
0.20
|
-12.02
|
|
250W
|
3.43
|
3.34
|
4.38
|
5.04
|
17.15
|
12.11
|
1.00
|
5.05
|
0.30
|
-12.04
|
|
500W
|
7.01
|
3.32
|
9.06
|
5.03
|
34.65
|
12.08
|
2.00
|
5.03
|
0.50
|
-12.06
|
| 750W |
11.00
|
3.32
|
13.69
|
5.03
|
52.77
|
12.06
|
2.50
|
5.01
|
0.60
|
-12.07
|
|
1000W
|
16.88
|
3.31
|
18.93
|
5.02
|
70.47
|
12.03
|
3.00
|
5.00
|
0.80
|
-12.07
|
This power supply produced fantastic load regulation across all outputs, even when delivering the full 1000W. All rails held within 1.5% of the reference voltage, well in excess of the +/-5% threshold.
| Powercolor Extreme Series 1000W | Maximum Load |
| 1102W |
We managed to get another 102W from the power supply before the protection circuitry kicked in. We are happy to report a safe shut down verifying that the overcircuit protection is doing its job.
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 | |
| 885W | 2.0 | 3.32 | 2.0 | 5.05 | 72.0 | 11.98 | 0.2 | -12.00 | 0.50 | 5.01 |
| 240W | 20.0 | 3.30 | 24.0 | 4.99 | 2.0 | 12.08 | 0.2 | -12.01 | 0.50 | 4.98 |
The Powercolor PSU handled the Cross loading tests very well and we didn’t experience any issues at all. All the voltages remained well within specification.
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 Power Color unit complied with the ATX standard.
| AC Ripple (mV p-p) | ||||
| DC Load | +3.3V | +5V | +12V | 5VSB |
| 100W | 5 | 5 | 5 | 5 |
| 250W | 10 | 5 | 10 | 5 |
| 500W | 10 | 5 | 20 | 10 |
| 750W | 15 | 10 | 30 | 10 |
| 1000W | 20 | 15 | 45 | 20 |
The Powercolor Extreme Series 1000W PSU delivered an excellent set of results and while it is not a flat line result, the figures are well within rated tolerance specifications.
|
Efficiency (%)
|
|
|
100W
|
85.02
|
|
250W
|
86.12
|
|
500W
|
87.02
|
|
750W
|
84.57
|
|
1000W
|
82.13
|
The efficiency results were very good indeed for a 80 Plus Bronze rated unit with a high point just over 87% at 50% load. The lowest was just over 82% efficiency at 100% load.
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 SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) 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)
|
|
|
100W
|
17.3
|
|
250W
|
18.2
|
|
500W
|
19.4
|
|
750W
|
28.8
|
| 1000W | 34.3 |
The Powercolor Extreme Series 1000W PSU remains silent under 50% load and slowly starts becoming audible at just under 700W, under 250W we noticed the fan wasn't spinning at all. Once it is pushed to 800W then the fan comes into full force, peaking at just over 34 dBA at 100% load. These are excellent results which show that the fan selection and configuration is very good.
|
Temperature (c)
|
||
|
Intake
|
Exhaust
|
|
|
100W
|
35
|
37
|
|
250W
|
35
|
38
|
|
500W
|
37
|
41
|
|
750W
|
40
|
47
|
|
1000W
|
43
|
52
|
The large fan handles air flow very well and under 50% load the exhaust temperature doesn’t rise that much compared to the intake air. Only around 700W does the fan spin up more to help compensate for rising ambient temperatures. A very good balance of low noise levels with strong air flow.
|
Maximum load
|
Efficiency
|
|
1102W
|
81.21
|
Pushing the PSU above its rated limits generates an efficiency level of around 81.21%. This is not a viable ‘real world’ situation, but its interesting nonetheless.
