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Enermax Platimax 1200W Power Supply review

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 combine all +12V output for results.

DC Output Load Regulation

Combined

DC Load

+3.3V
+5V
+12V
+5VSB
-12V
A
V
A
V
A
V
A
V
A V
330W
5.53
3.39
5.52
5.04
21.22
12.19
0.85
5.02
0.20 -12.13
620W
11.02
3.35
11.03
5.03
42.53
12.08
1.74
5.01
0.40 -12.10
918W
16.54
3.32
16.48
4.98
63.71
11.88
2.64
4.98
0.60 -12.06
1204W
22.03
3.27
22.01
4.94
85.01
11.84
3.6
4.95
0.80 -12.02
Platimax 1200W
Maximum Load
1345W

We managed to get 1345W from the unit before it would switch off. The overcircuit protection system worked well and it shut off 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
1190W 4.0 3.35 3.0 5.04 88.0 11.85 0.20 -12.04 0.50 5.01
195W 19.0 3.27 22.0 4.96 2.5 12.19 0.20 -12.08 0.50 4.96

The Cross loading performance is first class, thanks to the specific unit design methodology. All voltages remained within stated tolerances.

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
330W 10 10 10 15
620W 10 10 20 15
918W 15 15 25 15
1204W 20 25 30 20

Noise suppression is superb and well within the parameters set down in the ATX12V Ver 2.2 standard. +3.3V and +5V are extremely impressive and the +12V rail is also noteworthy, settling at 30mV under full load.

Efficiency (%)
330W
90.89
620W
93.45
918W
91.76
1204W
90.01

Efficiency is excellent, peaking at 93.45% when under 50% load. Efficiency drops to around 90% at full load which is a very strong result indeed.

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)
330W
29.4
620W
30.7
918W
33.2
1204W
34.5

This is a very quiet power supply, even when tasked with a power output of 900W. It would barely be audible above the majority of case fans. At full load it becomes audible, but it is still far from intrusive. Very impressive results indeed.

Temperature (c)
Intake
Exhaust
330W
35
36
620W
38
42
918W
42
48
1204W
46
54

The large Twister fan pushes an impressive amount of air, while making very little noise. This means that the unit holds a very positive above ambient as can be seen above.

Maximum load
Efficiency
1345W
87.1

Pushing the PSU above its rated limits generates an efficiency level of around 87.1%. This is not a viable ‘real world’ situation, but its interesting nonetheless.

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