Cooler Master Silent Pro Gold 1200W Power Supply Review

1. Introduction2. Cooler Master Silent Pro Gold 1200W (External)3. Cooler Master Silent Pro Gold 1200W (Internal)4. Testing Methodology and Results5. Closing Thoughts6. View All Pages

A few weeks ago we reviewed the Coolermaster Silent Pro Gold 600W, an extremely impressive power supply on a variety of levels. While 600W should be enough for most systems, there will always be a more demanding audience who need higher levels of power.

For this particular audience we will look at the highest power output model in the Silent Pro Gold range, the 1200W model.

Can this monster supply hold its own against the incredible class leading Corsair AX1200 that walked away with our top award in July this year?

• Heat Transfer Technology
  A unique “L-shaped” heat-sink to remove heat from the PSU
• Hybrid Transformer
  Unique design that combines heat-sink with transformer
• Hyper Path
  Places IC close to transformers leading to huge efficiency ratings
• Flat modularized cables provide easy cable management leads to better airflow
• Compliance with the latest Intel standard ATX 12V V2.3
• Operation with intelligent fan speed control
• High reliability (MTBF> 100,000 hours)
• Multiple protection design (OVP/UVP/OPP/OTP/SCP/OCP)
• Japanese-made capacitors
• Five-year warranty

You don't get much more eye catching than this. a box made from liquid gold. Well not really, but it certainly catches the eye.

Inside, the Supply is protected by foam and is shipped inside a protective bag to stop any damage to the surface under rough shipping conditions. On top is a user manual with specifications and to the right is a box containing the accessories and cabling.

The cables are extra length:

Hardwired:
ATX connector is 500mm.
4+4 Pin ATX12V/EPS12V is 600mm.
6+2 Pin PCIe is 610mm.
6 pin PCIe is +90mm

Modular:
6+2 pin PCIe is 600mm
6 pin PCIe is +100mm
Molex is 450mm + 95mm
floppy drive connector +100

As we noted last time, the finish is stunning, it doesn't attract finger prints easily and is fairly resilient to rough handling. This may sound like a small point, but I have had power supplies get scuffed when installing them carefully into a chassis. Simple and understated design, always a good combination.

The rear of the PSU is fully honeycomb vented to ensure maximum air flow and cooling proficency. The front supports the modular cables detailed earlier, and they are all clearly labelled and sized to ensure no one will get confused. The ports all match the muted gold colour scheme, a nice touch.

98A on the single 12V enough for you? Yeah we thought so, its enough for us as well.

The 600W model in this range used an Adda D1212MS-A71GL 120mm fan, but this time Cooler Master are using a 135mm x 135mm x 25mm Young Lin Tech Co. DFS132512H fan. This is another high quality unit which is capable of producing massive levels of airflow, when needed.

The layout is clean and has a L shaped heatsink cooling methodology which should help force heat outside the chassis environment. Soldering quality is high throughout. This is an Active PFC design which offers full protection for OVP/UVP/OCP/OPP/OTP and SCP.

The AC Transient filter, with two X caps and two Y caps. The design also places the IC close to the transformers which are required to create the high efficiency ratings. It complies with the latest Intel ATC 12V V2.3 standard and there is a double layer EMI filter to help reduce noise.

Primary Capacitors are Nippon Chemi-Con units. There are two VRM's to handle the minor rails. Secondary side capactors are a mixture from Sanyo, Nippon Chemi-Con and Teapo.

Fully sleeved into the chassis, always good to see as no chance of fraying can occur over time.

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

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
330W	5.50	3.35	5.50	5.04	21.25	12.10	0.87	5.02	0.20	-12.15
620W	11.00	3.33	11.00	5.04	42.50	12.08	1.75	5.01	0.40	-12.17
918W	16.50	3.31	16.50	5.03	63.75	12.04	2.62	4.99	0.60	-12.18
1204W	22.00	3.29	22.00	4.99	85.00	12.01	3.5	4.97	0.80	-12.20

The Cooler Master PSU maintains good voltage regulation across all the outputs and handles the load tests well. Primary rails all remained within 2 percent of nominal voltage.

Cooler Master Silent Pro Gold 1200W	Maximum Load
	1321W

We managed to coak just over 1320W out of the PSU before it would shut down, gracefully. We are happy to report that the overcircuit protection works well.

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	1.0	3.35	1.0	5.05	62.0	12.05	0.05	-12.15	0.05	5.01
195W	22.0	3.28	22.0	4.96	1.0	11.97	0.05	-11.97	0.05	4.97

A very good set of results under cross loading, only minor fluctuation, more noticeable on the -12V 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 Cooler Master unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
330W	10	15	20	15
620W	20	15	30	20
918W	25	25	60	25
1204W	30	35	85	30

Ripple results are higher than we normally record in our power supply reviews, with the 12V output maxing at around 85mv. This is not worrying however as it is still well within specifications (120mv). We wouldn't class this unit as having fantastic ripple suppression, but they are all well within specifications. Bear in mind that at 900W the 12v recorded around 60mv, within the lower half of the recommended tolerance levels.

Efficiency (%)
330W	88.9
620W	91.8
918W	90.4
1204W	88.5

Efficiency is good throughout the range, peaking at around 92% at 600W.

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 Corsair 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)
330W	26.4
620W	27.8
918W	30.5
1204W	35.8

A fantastic set of results, with the unit only audible at the higher end of the power scale. Under most real world conditions, it registers below 30 dBa.

Temperature (c)
	Intake	Exhaust
330W	35	37
620W	35	37
918W	38	42
1204W	43	53

The fan is optimised for a low noise balance, but due to the efficiency of the unit, the temperatures are only 10c over ambient at full load, which is a very impressive set of results.

Maximum load	Efficiency
1321W	86.7%

At 1321W the Cooler Master Gold PSU rated at 86.7 percent efficiency. This is not a viable ‘real world’ situation, but its interesting nonetheless.

The Cooler Master Silent Pro Gold 1200W is a fantastic power supply which clears 80 Plus Gold certification. While it isn't quite as efficient as the groundbreaking Corsair AX1200 it is still an extremely capable product.

In regards to ripple, it is certainly higher than the Corsair AX1200 by a significant margin, but it falls well within tolerance guidelines and will pose no issues for an end user.

Aesthetics are very much a personal choice, but we would imagine no one would find this design offensive or ugly. The subdued colour scheme and attractive paint process heightens the appearance of a quality product.

The Cooler Master Silent Pro Gold 1200w however earns massive brownie points for the extremely competitive pricing in the UK. Many stores are selling it for £190 inc vat, which is £40-£80 less than other 1200W+ units currently on the market. Sure, the ripple results aren't up there with the best of the them, but in reality this makes very little difference to the end user.

Noise levels are great, with the unit only becoming audible at the higher end of the power scale, unrealistic conditions for most people long term. Even those handful of enthusiast users requiring more than 900W will be likely gaming at the time, so it would go unnoticed.

Kitguru says: At this price point it is a product that should be at the top of your high performance shortlist.

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