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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
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DC Output Load Regulation
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||||||||
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Combined DC Load |
+3.3V
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+5V
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+12V
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+5VSB
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||||
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A
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V
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A
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V
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A
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V
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A
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V
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|
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75W
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1.02
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3.35
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1.45
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5.05
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4.88
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12.07
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0.50
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5.02
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|
150W
|
2.43
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3.34
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3.15
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5.05
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9.72
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12.05
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1.00
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5.02
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|
250W
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3.64
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3.34
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5.18
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5.04
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16.53
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12.04
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1.50
|
5.02
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| 350W |
4.93
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3.34
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7.08
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5.04
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23.51
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12.03
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2.00
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5.02 |
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450W
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6.77
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3.34
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9.16
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5.03
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32.76
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12.02
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2.50
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5.01
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Load regulation is excellent and all output maintain close to reference results.
| Corsair SF 450 | Maximum Load |
| 519 watts |
We managed to push the supply to 519 watts before it would shut down safely.
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 | |
| 386W | 2.0 | 3.35 | 2.0 | 5.05 | 30.0 | 12.01 | 0.2 | -12.03 | 0.50 | 5.02 |
| 171W | 18.0 | 3.33 | 12.0 | 5.02 | 4.0 | 12.06 | 0.2 | -12.04 | 0.50 | 5.01 |
Our first test placed a heavy load (30a) on the +12 V output with a light load on the remaining voltages. The power supply had no problems dealing with the load changes.
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.
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ATX12V Ver 2.2 Noise/Ripple Tolerance
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Output
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Ripple (mV p-p)
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|
+3.3V
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50
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+5V
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50
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|
+12V1
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120
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+12V2
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120
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-12V
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120
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+5VSB
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50
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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 unit complied with the ATX standard.
| AC Ripple (mV p-p) | ||||
| DC Load | +3.3V | +5V | +12V | 5VSB |
| 75W | 10 | 10 | 15 | 5 |
| 150W | 10 | 10 | 20 | 5 |
| 250W | 15 | 10 | 25 | 5 |
| 350W | 15 | 15 | 30 | 10 |
| 450W | 15 | 15 | 30 | 10 |
Ripple suppression is stellar, with both +3.3V and +5V peaking at 15mV. The +12V rail hit a maximum of 30mV at full load.
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Efficiency (%)
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|
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75W
|
86.75
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150W
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88.33
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|
250W
|
92.04
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|
350W
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90.34
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450W
|
88.85
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The Corsair SF450 is a very efficient unit, peaking at around 92% at 50% load. This drops to around 89% at full 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
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Noise (dBA)
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|
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75W
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<28.0
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150W
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<28.0
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250W
|
31.4
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|
350W
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32.2
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| 450W | 33.3 |
The 92mm fan spins slowly under 200 watts load, spinning up at around 300W and greater. At full load you can barely hear the fan.
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Temperature (c)
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||
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Intake
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Exhaust
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|
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75W
|
35
|
38
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150W
|
36
|
44
|
|
250W
|
39
|
48
|
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350W
|
42
|
58
|
|
450W
|
45
|
60
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The supply holds a good temperature variable – rising to a 15c peak at full load.
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Maximum load
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Efficiency
|
|
519W
|
88.33
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Pushing the power supply above its rated limits generates an efficiency level of around 88%. This is not a viable ‘real world’ situation, but its interesting nonetheless.
It would have been nice to have a direct comparison with the Silverstone versions. I have a SX600-G myself and sometimes I think I can hear the fan getting a bit noisier than I would like. It’s in a small case (Case: Fractal Design Core 500), so it’s not always easy to hear what is causing the noise. I also have a weird chirping echo after about 15 minutes from cold boot. I still haven’t figured out what that is. I can hear a slight squeaking noise that gets slightly louder (still all very quiet) and then it does the echoing noise. After that it stops making the sound. But I still haven’t figured out what is causing it. It doesn’t seem to cause any problems, so I’m not too fussed as it’s too much effort to keep taking it apart.
Were these tested at 115VAC input or 230VAC input? I noticed you listed a Variac in your list of test equipment so you can better sync with Ecova’s test results, but it doesn’t hurt to ask. 😉
it said 7 years warranty on the corsair web
The site SWEclockers seem to have gotten a better model, measuring only 23 mV max ripple on the 12 Volt rail.. I guess that could be manufacturing variance or a different approach to taking measurements. :p
Either way, I’m glad I found this PSU. There’s some PSU test site that tests in far more detail than Kitguru, but I couldn’t remember the site’s name. That’s not to say Kitguru’s test was insufficient – they make a lot more effort than most other sites that “test” PSU’s.
My Sharkoon 600W SFX-L wasn’t bad, but it ran hotter and its modular connectors were pushing hard against the back of the GPU in my NCase M1. A little too close for NCase’s claim that SFX-L PSUs will “fit”.
I never bought anything from Corsair before, but I might check out their coolers, since my Noctua cooler refused to fit into my case as well…
Silverstone has some brilliant engineering for case layout and airflow. But the company has a bad habit of building things as cheaply as possible. Granted, I’m used to Lian Li, which is at about the opposite end of the quality spectrum, but Lian Li too often bumbles space optimization and cooling concepts instead. Its anyone’s guess what’s worse in the end.
But after having built in some of Silverstone’s cases, I stopped well short of wanting to gamble on one of their PSUs, especially because I couldn’t find any thorough test at the time. Too many sites call something “test” and then just paraphrase the corporate press release for the product.
At any rate, if your PC is running and never has random crashes, your’s must be good enough. The only way to reduce the noise from your SX600G would be to put in a better and/or larger fan, voiding the warranty in the process.
If I was you and the noise got on my nerves, I’d buy the Corsair PSU and ebay the other one, while its still a current model.