CORSAIR AX1600i Digital Power Supply Review

1. Introduction2. Bundle & Cabling3. External4. Internal5. Testing Methodology & Results6. Closing Thoughts7. View All Pages

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
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

We test in single rail mode.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
150W	0.88	3.34	0.84	5.03	11.60	12.09	0.5	5.01	0.20	-12.03
300W	1.62	3.34	1.63	5.03	24.02	12.08	1.0	5.01	0.20	-12.03
750W	3.00	3.34	3.06	5.03	60.21	12.04	1.5	5.01	0.30	-12.03
1125W	4.00	3.33	4.07	5.02	90.00	12.03	2.0	5.00	0.30	-12.04
1500W	15.79	3.33	15.56	5.02	113.90	12.02	2.5	5.00	0.50	-12.04
1600W	9.23	3.33	9.12	5.03	126.60	12.00	3.0	5.00	0.50	-12.05

Load regulation is class leading, even when delivering the full 1600 watts of power.

CORSAIR AX1600i Digital Power Supply	Maximum Load
	1808W

We managed to get the PSU to achieve 1808W before it would shut down, delivering around 208W more than the rated specifications. It shut down safely when we pushed it beyond the limits and was ready again for a more sensible demand.

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
1150W	3.0	3.34	2.0	5.04	92.0	12.04	0.2	-12.03	0.50	5.01
250W	20.0	3.33	24.0	5.02	5.0	12.08	0.2	-12.03	0.50	5.01

The Corsair AX1600i 1600W produced some stunning results in the cross loading test. No discernible weaknesses at all.

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 unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
500W	5	5	10	5
750W	5	5	10	5
1000W	5	5	10	5
1250W	5	5	10	5
1500W	5	5	15	5
1600W	10	10	15	5

Class leading ripple suppression peaking at 10mV on both +3.3V and +5V rails. The +12V rail peaked at 15mV. Stellar results all round for the AX1600i.

Efficiency (%)
500W	95.21
750W	97.31
1000W	96.78
1250W	96.21
1500W	95.79
1600W	95.11

Overall efficiency is excellent, peaking at 97.3% when delivering between 750 and 850 watts. At full load we recorded an efficiency of 95.1% which is remarkable.

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 Refrigerator
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)
500W	/
750W	28.3
1000W	29.7
1250W	31.4
1500W	33.3
1600W	34.1

Thanks to the extremely high efficiency of this power supply and the high grade fan the unit never emits much noise at all, even under high 1000 watt+ loads. At lower loads (anything at 600 watts or lower) the fan didn't spin at all. That's the Corsair Zero RPM working its magic.

Temperature (c)
	Intake	Exhaust
500W	36	39
750W	37	42
1000W	42	47
1250W	46	51
1500W	48	54
1600W	51	60

The large fan is inactive until about 650 watt load when it comes into action, spinning very slowly. At 100% load the fan was spinning around 1,200 rpm – which is still rather slow spinning.

Maximum load	Efficiency
1808W	94.72

At 1808W, the efficiency level is still good, measuring 94.72%. Not a practical situation to be running 24/7, but worth noting.

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