PC Power & Cooling Silencer Mk III 750 W Power Supply Review
By Gabriel Torres on February 1, 2013


Introduction

Hardware Secrets Silver Award

The PC Power & Cooling Silencer Mk III power supply series has models ranging from 400 W to 1,200 W. Models from 400 W to 600 W have the 80 Plus Bronze certification, while the 750 W and 850 W models have the 80 Plus Gold certification, and the 1,200 W model has the 80 Plus Platinum certification. Let’s test the 750 W model and see if it is a good buy.

While models from 400 W to 600 W are manufactured by Seasonic, other models are manufactured by Super Flower. The 750 W model is based on Super Flower’s Golden Green platform, which is also used by the Rosewill CAPSTONE-750, the Rosewill CAPSTONE-750M, the Sentey GSP750-SM, and the NZXT HALE90-750-M. Although these power supplies are internally identical, externally the PC Power & Cooling Mk III 750 W is different, using a modular cabling system with rounded connectors and with a switch to configure the fan’s mode of operation.

PC Power and Cooling Silencer MKIII 750w
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Figure 1: PC Power & Cooling Silencer Mk III 750 W power supply

PC Power and Cooling Silencer MKIII 750w
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Figure 2: PC Power & Cooling Silencer Mk III 750 W power supply

The PC Power & Cooling Silencer Mk III 750 W is 7.1” (180 mm) deep. It uses a 140 mm ball-bearing fan on its bottom (Globe Fan RL4ZB1402512H). The power supply has a “hybrid/normal” switch that allows you to configure the fan to turn on only when the power supply load reaches 350 W, so the power supply won’t make any noise when the computer doesn’t demand a lot of power.

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Figure 3: Fan

The modular cabling system from this power supply has eight connectors: four for video cards and four for peripheral and SATA connectors. This power supply comes with the following cables:

All wires are 18 AWG, which is the minimum recommended gauge.

This is a somewhat standard configuration for 750 W units, with the advantage of having a total of 12 SATA power connectors.

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Figure 4: Cables

Let’s now take an in-depth look inside this power supply.

A Look Inside the PC Power & Cooling Silencer Mk III 750 W

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.            

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

PC Power and Cooling Silencer MKIII 750w
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Figure 5: Top view

PC Power and Cooling Silencer MKIII 750w
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Figure 6: Front quarter view

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Figure 7: Rear quarter view

PC Power and Cooling Silencer MKIII 750w
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Figure 8: The printed circuit board

Transient Filtering Stage

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

In the transient filtering stage, this power supply doesn’t have an MOV, which is in charge of removing spikes coming from the power grid.

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Figure 9: Transient filtering stage

On the next page, we will have a more detailed discussion of the components used in the PC Power & Cooling Silencer Mk III 750 W.

Primary Analysis

On this page, we will take an in-depth look at the primary stage of the PC Power & Cooling Silencer Mk III 750 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.          

This power supply uses one US30K80R rectifying bridge, which is attached to an individual heatsink. This bridge supports up to 30 A at 97° C. In theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 2,760 W without burning itself out (or 3,105 W at 90% efficiency). Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

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Figure 10: Rectifying bridge

The active PFC circuit uses two IPP50R199CP MOSFETs, each one supporting up to 17 A at 25° C or 11 A at 100° C in continuous mode (note the difference temperature makes), or 40 A at 25° C in pulse mode. These transistors present a 199 mΩ maximum resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.   

The active PFC circuit is controlled by an NCP1653 integrated circuit.

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Figure 11: Active PFC controller

The output of the active PFC circuit is filtered by one 560 μF x 400 V Japanese electrolytic capacitor, from Chemi-Con, labeled at 105° C.

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Figure 12: Capacitor

In the switching section, another two IPP50R199CP MOSFETs are employed using a resonant configuration. The specifications for these transistors were already discussed above.  

PC Power and Cooling Silencer MKIII 750w
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Figure 13: The switching transistors, the active PFC diode, and the active PFC transistors

The switching transistors are controlled by an SF29601 resonant controller, which is a proprietary integrated circuit from Super Flower.

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Figure 14: Resonant controller

Let’s now take a look at the secondary of this power supply.

Secondary Analysis

As one would expect in a high-efficiency power supply, the PC Power & Cooling Silencer Mk III 750 W uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses four IPP041N04N MOSFETs, each one supporting up to 80 A at 100° C in continuous mode, or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 4.1 mΩ.

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Figure 15: The +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, which are located on a daughterboard. Each converter is controlled by an NCP1587 integrated circuit, and each converter makes use of four IPD060N03L G transistors. Each transistor supports up to 50 A at 100° C in continuous mode and up to 350 A at 25° C in pulse mode, with a maximum RDS(on) of 6 mΩ.

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Figure 16: The DC-DC converters

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Figure 17: The DC-DC converters

We couldn’t find any specific integrated circuit for monitoring the outputs and implementing the proper protections.

This power supply uses Japanese electrolytic capacitors in its secondary, from Chemi-Con, labeled at 105° C, as usual.

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Figure 18: Capacitors

PC Power and Cooling Silencer MKIII 750w
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Figure 19: Capacitors

The +5VSB Power Supply

The +5VSB (a.k.a. standby) power supply is independent of the main power supply, since it is on continuously.

The +5VSB power supply uses an ICE3B0565 integrated circuit, which incorporates the PWM controller and the switching transistor into a single chip.

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Figure 20: The +5VSB integrated circuit with an integrated switching transistor

The rectification of the +5VSB output is performed by an S10C60C Schottky rectifier, which supports up to 10 A (5 A per internal diode at 125° C, 0.70 V maximum voltage drop).

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Figure 21: The +5VSB rectifier

Power Distribution

In Figure 22, you can see the power supply label containing all the power specs.

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Figure 22: Power supply label

As you can see, this unit has a single +12 V rail configuration.

Let’s find out how much power this unit can deliver.

Load Tests

We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.”        

First, we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at 5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector.)

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

5.5 A (66 W)

11.5 A (138 W)

17 A (204 W)

22.5 A (270 W)

28.5 A (342 W)

+12VB

5.5 A (66 W)

11 A (132 W)

16.5 A (198 W)

22 A (264 W)

28.25 A (339 W)

+5 V

1 A (5 W)

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

+3.3 V

1 A (3.3 W)

2 A (6.6 W)

4 A (13.2 W)

6 A (19.8 W)

8 A (26.4 W)

+5VSB

1 A (5 W)

1.5 A (7.5 W)

2 A (10 W)

2.5 A (12.5 W)

3 A (15 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

152.6 W

300.4 W

448.8 W

599.8 W

751.4 W

% Max Load

20.3%

40.1%

59.8%

80.0%

100.2%

Room Temp.

46.5° C

45.7° C

46.4° C

48.0° C

49.0° C

PSU Temp.

47.2° C

48.3° C

49.5° C

51.0° C

53.1° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

170.8 W

333.2 W

502.5 W

678.0 W

883.0 W

Efficiency

89.3%

90.2%

89.3%

88.5%

85.1%

AC Voltage

117.3 V

115.6 V

114.1 V

112.3 V

110.3 V

Power Factor

0.984

0.987

0.992

0.993

0.995

Final Result

Pass

Pass

Pass

Pass

Pass

The 80 Plus Gold certification promises efficiency of at least 87% under light (i.e., 20%) load, 90% under typical (i.e., 50%) load, and 87% under full (i.e., 100%) load. During our tests, the PC Power & Cooling Silencer Mk III 750 W wasn’t able to present 87% efficiency at full load under high temperatures. As we always point out, the tests for the 80 Plus certification are conducted at only 23° C, and efficiency decreases as temperature increases. Another explanation is the fact that the AC voltage dropped to 110 V during our test five, and efficiency is lower at lower AC voltages.

Let’s discuss voltage regulation on the next page.

Voltage Regulation Tests

The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values. We consider a power supply as “flawless” if it shows voltages within 3% of their nominal values. In the table below, you can see the power supply voltages during our tests and, in the following table, the deviation, in percentage, of their nominal values.

The PC Power & Cooling Silencer Mk III 750 W presented voltages within the allowed margin.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

+12.12 V

+12.06 V

+11.98 V

+11.92 V

+11.86 V

+12VB

+12.10 V

+12.02 V

+11.90 V

+11.80 V

+11.72 V

+5 V

+5.10 V

+5.05 V

+4.99 V

+4.92 V

+4.84 V

+3.3 V

+3.33 V

+3.27 V

+3.22 V

+3.16 V

+3.15 V

+5VSB

+5.03 V

+4.96 V

+4.89 V

+4.82 V

+4.78 V

-12 V

-12.00 V

-12.03 V

-12.07 V

-12.11 V

-12.12 V


Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

1.00%

0.50%

-0.17%

-0.67%

-1.17%

+12VB

0.83%

0.17%

-0.83%

-1.67%

-2.33%

+5 V

2.00%

1.00%

-0.20%

-1.60%

-3.20%

+3.3 V

0.91%

-0.91%

-2.42%

-4.24%

-4.55%

+5VSB

0.60%

-0.80%

-2.20%

-3.60%

-4.40%

-12 V

0.00%

-0.25%

-0.58%

-0.91%

-0.99%

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed  are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The PC Power & Cooling Silencer Mk III 750 W provided extremely low ripple and noise levels, as you can see in the table below.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

9.6 mV

15.4 mV

19.6 mV

24.8 mV

30.2 mV

+12VB

13.4 mV

20.0 mV

27.2 mV

33.8 mV

44.2 mV

+5 V

8.4 mV

10.2 mV

10.2 mV

11.8 mV

16.4 mV

+3.3 V

6.6 mV

8.4 mV

10.4 mV

13.4 mV

22.4 mV

+5VSB

4.2 mV

5.4 mV

7.2 mV

8.4 mV

13.8 mV

-12 V

11.8 mV

13.2 mV

15.4 mV

16.6 mV

27.2 mV

Below you can see the waveforms of the outputs during test five.

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Figure 23: +12VA input from load tester during test five at 751.4 W (30.2 mV)

PC Power and Cooling Silencer MKIII 750w
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Figure 24: +12VB input from load tester during test five at 751.4 W (44.2 mV)

PC Power and Cooling Silencer MKIII 750w
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Figure 25: +5V rail during test five at 751.4 W (16.4 mV)

PC Power and Cooling Silencer MKIII 750w
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Figure 26: +3.3 V rail during test five at 751.4 W (22.4 mV)

Let’s see if we can pull more than 750 W from this unit.

Overload Tests

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit passed this test, since it shut down when we tried to pull more than what is listed below. During this test, noise and ripple levels were still low and voltages were still within the allowed range, even though the +5 V and +3.3 V outputs were touching their lower limits.

Input

Overload Test

+12VA

32 A (384 W)

+12VB

32 A (384 W)

+5 V

15 A (75 W)

+3.3 V

15 A (49.5 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

891.4 W

% Max Load

118.9%

Room Temp.

45.4° C

PSU Temp.

54.8° C

AC Power

1,083 W

Efficiency

82.3%

AC Voltage

108.0 V

Power Factor

0.995

Main Specifications

The main specifications for the PC Power & Cooling Silencer Mk III 750 W power supply include:

* Researched at Newegg.com on the day we published this review.

Conclusions

During our tests, the PC Power & Cooling Silencer Mk III 750 W worked as expected, with voltages within specification, low noise and ripple levels, and high efficiency. You won’t regret it if you buy this product.

However, there are better 750 W units with the 80 Plus Gold certification around, in particular those manufactured by Seasonic, such as the XFX PRO 750 W Black Edition Full Modular, which provides better voltage regulation, lower noise and ripple levels, a fully modular cabling system, higher efficiency at full load, and the presence of a MOV – all of that for USD 10 less than the new model from PC Power & Cooling. Even though you can get a USD 15 rebate card when buying the Silencer Mk III 750 W, we still think the model from XFX (and other models based on the same platform, such as the Seasonic X-Series KM3 750 W and the Corsair AX760) is a better option for the savvy user.

Originally at http://www.hardwaresecrets.com/article/PC-Power-and-Cooling-Silencer-Mk-III-750-W-Power-Supply-Review/1722


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