Cooler Master Extreme 2 475 W Power Supply Review
By Gabriel Torres on May 11, 2012


Introduction

The new Extreme 2 entry-level power supply series from Cooler Master comes in four different versions: 475 W, 525 W, 625 W, and 725 W. They don’t have an active PFC circuit and, therefore, don’t carry the 80 Plus certification. Let’s take an in-depth look at the 475 W model, which costs only USD 50.

The first thing that caught our attention was that it isn’t written on the product box or product label  that the unit is a 475 W power supply. The manufacturer carefully avoided adding the letter “W” after “475,” a typical maneuver when the unit isn’t able to deliver its labeled wattage. This way, the manufacturer can claim that “475” is not the power supply wattage, but its model number. Also, it is written on the product supply label: “The +3.3 V & +5 V & +12V1 & +12V2 combine (sic) power shall not exceed 408.9 W.” If we add the 3.6 W limit of the -12 V output and the 12.5 W limit of the +5VSB, we have a 425 W power supply. However, the manufacturer’s website lists this unit as a 475 W model.

Cooler Master Extreme 2 475 W power supply
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Figure 1: Cooler Master Extreme 2 475 W power supply

Cooler Master Extreme 2 475 W power supply
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Figure 2: Cooler Master Extreme 2 475 W power supply

The Cooler Master Extreme 2 475 W is 5.5” (140 mm) deep, using a 120 mm sleeve bearing fan on its bottom (Young Lin DFS122512H).

The reviewed power supply doesn’t have a modular cabling system, and only the main motherboard cable has a nylon sleeve that comes from inside the unit. This power supply comes with the following cables:

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

Cooler Master Extreme 2 475 W power supply
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Figure 3: Cables

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

A Look Inside the Cooler Master Extreme 2 475 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.

Cooler Master Extreme 2 475 W power supply
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Figure 4: Top view

Cooler Master Extreme 2 475 W power supply
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Figure 5: Front quarter view

Cooler Master Extreme 2 475 W power supply
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Figure 6: Rear quarter view

Cooler Master Extreme 2 475 W power supply
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Figure 7: 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 is flawless, with one X capacitor and two Y capacitors more than the minimum required. There are two MOVs, installed between the two electrolytic capacitors from the voltage doubler circuit and not shown in the pictures below.

Cooler Master Extreme 2 475 W power supply
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Figure 8: Transient filtering stage (part 1)

Cooler Master Extreme 2 475 W power supply
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Figure 9: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the Cooler Master Extreme 2 475 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Cooler Master Extreme 2 475 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one GBU806 rectifying bridge, which is attached to the same heatsink as the switch transistors. This bridge supports up to 8 A at 100° C. So, in theory, you would be able to pull up to 920 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 736 W without burning itself out. Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

Cooler Master Extreme 2 475 W power supply
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Figure 10: Rectifying bridge

As mentioned, this unit doesn’t have an active PFC circuit. The voltage doubler circuit uses two 560 µF x 200 V electrolytic capacitors from Teapo, labeled at 105° C.

The Cooler Master Extreme 2 475 W uses a single-transistor forward configuration in its switching section. Two 2SK4115 MOSFETs are connected in parallel to double the maximum current the switching section supports. Each of these transistors supports up to 7 A at 25° C in continuous mode or up to 21 A at 25° C in pulse mode, with a maximum RDS(on) of 1.6 Ω, which is extremely high. Unfortunately, the manufacturer doesn’t publish the current limits at 100° C.

Cooler Master Extreme 2 475 W power supply
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Figure 11: One of the switching transistors

The primary is managed by a TL3843 PWM controller.

Cooler Master Extreme 2 475 W power supply
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Figure 12: PWM controller

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

Secondary Analysis

The Cooler Master Extreme 2 475 W uses a regular design in its secondary, with Schottky rectifiers.

The maximum theoretical current that each line can deliver is given by the formula I / (1 - D) where D is the duty cycle used and I is the maximum current supported by the rectifying diode. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses two BYQ30E Schottky rectifiers, each supporting up to 16 A (8 A per internal diode at 104° C with a 1.25 V maximum voltage drop, which is extremely high, i.e., low efficiency). This gives us a maximum theoretical current of 23 A or 274 W for the +12 V output.

The +5 V output uses two STPS2045CT Schottky rectifiers, each supporting up to 20 A (10 A per internal diode at 155° C with a 0.84 V maximum voltage drop). This gives us a maximum theoretical current of 29 A or 143 W for the +5 V output.

The +3.3 V output uses another two STPS2045CT Schottky rectifiers, giving us a maximum theoretical current of 29 A or 94 W for the +3.3 V output.

It is very interesting to note how the +12 V output uses rectifiers that are “weaker” than the ones used on the +5 V and +3.3 V outputs, a typical scenario from 15 years ago. Nowadays, the +12 V output must be “stronger” than the other outputs, since the components that consume the most current from the power supply (namely, the CPU and the video card) are connected to the +12 V output.

Cooler Master Extreme 2 475 W power supply
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Figure 13: One of the +3.3 V, +5 V, and +12 V rectifiers

This power supply uses a PS223 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), over temperature (OTP), and over current (OCP) protections. The over current protection has four channels (+5 V, +3.3 V, +12V1, and +12V2), correctly matching the number of +12 V rails advertised by the manufacturer (two).

Cooler Master Extreme 2 475 W power supply
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Figure 14: Monitoring circuit

The electrolytic capacitors that filter the outputs are also from Teapo and labeled at 105° C, as usual.

Power Distribution

In Figure 15, you can see the power supply label containing all the power specs.

Cooler Master Extreme 2 475 W power supply
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Figure 15: Power supply label

This power supply is advertised as having two +12 V rails, which is correct, since the monitoring integrated circuit has two +12 V over current protection (OCP) channels, and we clearly saw two current sensors (“shunts”) on the component side of the printed circuit board. See Figure 16. Click here to understand more about this subject.

Cooler Master Extreme 2 475 W power supply
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Figure 16: Shunts

The two +12 V rails are distributed as follows:

This is the typical distribution used by power supplies with two rails, and it is perfect.

How much power can this unit really deliver? Let’s find out.

Load Tests

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

Because we had no clue of the real wattage of this power supply, we tested it differently. Starting from 85 W, we increased the load little by little until we could see the maximum amount of power we could extract from the reviewed unit.

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 input was connected to the power supply +12V1 rail, while the +12VB input was connected to the power supply +12V2 rail.

Input

Test 1

Test 2

Test 3

Test 4

+12VA

3 A (36 W)

3.5 A (42 W)

4.25 A (51 W)

5.5 A (66 W)

+12VB

2.5 A (30 W)

3.25 A (39 W)

4.25 A (51 W)

5.5 A (66 W)

+5 V

1 A (5 W)

1 A (5 W)

1.5 A (7.5 W)

1.5 A (7.5 W)

+3.3 V

1 A (3.3 W)

1 A (3.3 W)

1.5 A (4.95 W)

1.5 A (4.95 W)

+5VSB

1 A (5 W)

1 A (5 W)

1 A (5 W)

1 A (5 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

90.3 W

102.0 W

126.9 W

152.8 W

% Max Load

19.0%

21.5%

26.7%

32.2%

Room Temp.

43.8° C

43.8° C

43.6° C

43.4° C

PSU Temp.

49.4° C

48.8° C

48.3° C

48.0° C

Voltage Regulation

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

AC Power

124.7 W

138.4 W

167.7 W

199.2 W

Efficiency

72.4%

73.7%

75.7%

76.7%

AC Voltage

116.1 V

116.7 V

115.7 V

115.5 V

Power Factor

0.641

0.653

0.663

0.669

Final Result

Pass

Pass

Pass

Pass


Input

Test 5

Test 6

Test 7

Test 8

+12VA

6.25 A (75 W)

7.25 A (87 W)

8.25 A (99 W)

9 A (108 W)

+12VB

6.25 A (75 W)

7.25 A (87 W)

8 A (96 W)

9 A (108 W)

+5 V

2 A (10 W)

2 A (10 W)

2.5 A (12.5 W)

2.5 A (12.5 W)

+3.3 V

2 A (6.6 W)

2 A (6.6 W)

2.5 A (8.25 W)

2.5 A (8.25 W)

+5VSB

1 A (5 W)

1 A (5 W)

1.5 A (7.5 W)

1.5 A (7.5 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

174.6 W

197.8 W

221.4 W

244.1 W

% Max Load

36.8%

41.6%

46.6%

51.4%

Room Temp.

43.6° C

43.8° C

43.8° C

44.1° C

PSU Temp.

47.9° C

48.0° C

48.4° C

49.2° C

Voltage Regulation

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

AC Power

225.0 W

254.3 W

285.8 W

316.0 W

Efficiency

77.6%

77.8%

77.5%

77.2%

AC Voltage

116.1 V

115.7 V

114.9 V

114.5 V

Power Factor

0.673

0.676

0.675

0.676

Final Result

Pass

Pass

Pass

Pass


Input

Test 9

Test 10

Test 11

Test 12

+12VA

10 A (120 W)

11 A (132 W)

12 A (144 W)

13 A (156 W)

+12VB

10 A (120 W)

11 A (132 W)

12 A (144 W)

13 A (156 W)

+5 V

3 A (15 W)

3 A (15 W)

3 A (15 W)

3 A (15 W)

+3.3 V

3 A (9.9 W)

3 A (9.9 W)

3 A (9.9 W)

3 A (9.9 W)

+5VSB

1.5 A (7.5 W)

1.5 A (7.5 W)

1.5 A (7.5 W)

1.5 A (7.5 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

270.8 W

292.4 W

315.3 W

337.8 W

% Max Load

57.0%

61.6%

66.4%

71.1%

Room Temp.

45.3° C

47.2° C

46.9° C

48.6° C

PSU Temp.

50.3° C

52.3° C

52.6° C

53.7° C

Voltage Regulation

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

AC Power

351.2 W

381.6 W

413.0 W

445.0 W

Efficiency

77.1%

76.6%

76.3%

75.9%

AC Voltage

114.1 V

114.2 V

114.6 V

114.5 V

Power Factor

0.676

0.677

0.68

0.681

Final Result

Pass

Pass

Pass

Pass


Input

Test 13

Test 14

Test 15

Test 16

+12VA

14 A (168 W)

15 A (180 W)

16 A (192 W)

17 A (204 W)

+12VB

14 A (168 W)

15 A (180 W)

16 A (192 W)

17 A (204 W)

+5 V

3 A (15 W)

3.5 A (17.5 W)

3.5 A (17.5 W)

3.5 A (17.5 W)

+3.3 V

3 A (9.9 W)

3.5 A (11.55 W)

3.5 A (11.55 W)

3.5 A (11.55 W)

+5VSB

1.5 A (7.5 W)

1.5 A (7.5 W)

1.5 A (7.5 W)

1.5 A (7.5 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

358.4 W

384.8 W

406.5 W

428.9 W

% Max Load

75.5%

81.0%

85.6%

90.3%

Room Temp.

49.2° C

46.6° C

45.8° C

45.0° C

PSU Temp.

54.8° C

55.9° C

57.3° C

59.0° C

Voltage Regulation

Pass

Fail on +12 V

Fail on +12 V

Fail on +12 V

Ripple and Noise

Pass

Pass

Pass

Fail on +5 V and -12 V

AC Power

479.0 W

521.0 W

563.0 W

608.0 W

Efficiency

74.8%

73.9%

72.2%

70.5%

AC Voltage

113.8 V

113.0 V

110.9 V

110.6 V

Power Factor

0.682

0.683

0.681

0.681

Final Result

Pass

Fail

Fail

Fail

The Cooler Master Extreme 2 475 W can only deliver up to 430 W. When we tried to pull more than that, the power supply burned. (The component that burned was one of the switching transistors.) But, you can only safely pull up to 360 W from it. When pulling above 360 W, the +12 V outputs drop below the minimum allowed.

Efficiency was between 70.5% and 77.8%, clearly indicating that this unit is a low-end product.

Voltage Regulation

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. In the tables below, we show the voltage results for the reviewed power supply. We marked in red the values that were outside the allowed range.

Input

Test 1

Test 2

Test 3

Test 4

+12VA

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+12VB

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+5 V

+5.20 V

+5.20 V

+5.19 V

+5.20 V

+3.3 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+5VSB

≤ 3%

≤ 3%

≤ 3%

≤ 3%

-12 V

-11.61 V

-11.64 V

-11.69 V

-11.71 V


Input

Test 5

Test 6

Test 7

Test 8

+12VA

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+12VB

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+5 V

+5.18 V

+5.18 V

+5.16 V

+5.17 V

+3.3 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+5VSB

≤ 3%

≤ 3%

≤ 3%

≤ 3%

-12 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%


Input

Test 9

Test 10

Test 11

Test 12

+12VA

+11.61 V

+11.55 V

+11.53 V

+11.49 V

+12VB

+11.62 V

+11.57 V

+11.54 V

+11.49 V

+5 V

+5.16 V

+5.17 V

+5.18 V

+5.19 V

+3.3 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+5VSB

≤ 3%

≤ 3%

≤ 3%

≤ 3%

-12 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%


Input

Test 13

Test 14

Test 15

Test 16

+12VA

+11.43 V

+11.39 V

+11.37 V

+11.33 V

+12VB

+11.42 V

+11.37 V

+11.34 V

+11.31 V

+5 V

+5.19 V

+5.18 V

+5.19 V

+5.20 V

+3.3 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%

+5VSB

≤ 3%

≤ 3%

≤ 3%

≤ 3%

-12 V

≤ 3%

≤ 3%

≤ 3%

≤ 3%

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.

In the tables below, you can see the noise and ripple levels for the Cooler Master Extreme 2 475 W during our tests. We marked in red the values that were above the allowed range.

Input

Test 1

Test 2

Test 3

Test 4

+12VA

16.4 mV

16.0 mV

17.2 mV

19.4 mV

+12VB

17.0 mV

16.8 mV

19.4 mV

21.8 mV

+5 V

11.2 mV

11.8 mV

12.6 mV

15.0 mV

+3.3 V

9.2 mV

9.4 mV

10.2 mV

11.8 mV

+5VSB

12.2 mV

12.6 mV

12.8 mV

14.2 mV

-12 V

16.4 mV

17.4 mV

22.2 mV

22.4 mV


Input

Test 5

Test 6

Test 7

Test 8

+12VA

19.8 mV

23.2 mV

24.6 mV

28.0 mV

+12VB

23.8 mV

28.2 mV

29.2 mV

33.2 mV

+5 V

15.8 mV

15.8 mV

16.4 mV

18.2 mV

+3.3 V

12.2 mV

13.8 mV

14.4 mV

15.4 mV

+5VSB

14.4 mV

15.6 mV

16.8 mV

17.4 mV

-12 V

32.8 mV

33.6 mV

37.2 mV

42.2 mV


Input

Test 9

Test 10

Test 11

Test 12

+12VA

31.4 mV

37.4 mV

40.0 mV

50.2 mV

+12VB

36.6 mV

42.2 mV

45.2 mV

56.6 mV

+5 V

19.4 mV

18.8 mV

20.8 mV

23.6 mV

+3.3 V

16.2 mV

17.4 mV

18.2 mV

20.2 mV

+5VSB

17.8 mV

18.6 mV

19.4 mV

20.2 mV

-12 V

46.2 mV

43.0 mV

50.6 mV

54.4 mV


Input

Test 13

Test 14

Test 15

Test 16

+12VA

52.8 mV

70.2 mV

72.4 mV

78.2 mV

+12VB

58.6 mV

74.6 mV

77.8 mV

83.8 mV

+5 V

33.2 mV

32.2 mV

41.0 mV

50.4 mV

+3.3 V

21.2 mV

22.0 mV

24.2 mV

25.8 mV

+5VSB

20.4 mV

21.8 mV

21.8 mV

26.4 mV

-12 V

78.4 mV

78.6 mV

100.8 mV

129.2 mV

Below you can see the waveforms of the outputs during test 16.

Cooler Master Extreme 2 475 W power supply
click to enlarge
Figure 17: +12VA input from load tester during test 16 at 428.9 W (78.2 mV)

Cooler Master Extreme 2 475 W power supply
click to enlarge
Figure 18: +12VB input from load tester during test 16 at 428.9 W (83.8 mV)

Cooler Master Extreme 2 475 W power supply
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Figure 19: +5V rail during test 16 at 428.9 W (50.4 mV)

Cooler Master Extreme 2 475 W power supply
click to enlarge
Figure 20: +3.3 V rail during test 16 at 428.9 W (25.8 mV)

Main Specifications

The main specifications for the Cooler Master Extreme 2 475 W power supply include:

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

Conclusions

We think it is simply ridiculous that in this day and age there are still well-known brands labeling power supplies with fake wattages. In the case of the Cooler Master Extreme 2 475 W, we can clearly see that this was done deliberately, as the product box and label list “475” without the letter “W” or the word “Watts” after it, probably to protect themselves in the case of an eventual lawsuit, by claiming that “475” is the “model” of the power supply, not its wattage. However, the manufacturer’s website clearly lists this unit as being a 475 W model. Of course, we are against this kind of practice, and Cooler Master may face problems with agencies in charge of regulating the power supply market around the world.

Even if this unit were labeled with its real wattage (430 W), it would still be a bad choice. Voltages drop below the minimum allowed, and noise and ripple levels can increase above the maximum allowed, causing your computer to behave erratically. Also, this unit presents low efficiency.

There are better power supplies at the same wattage costing less.

In summary, we must recommend that you stay away from this power supply.

Updated 06/28/2012:

Cooler Master’s Official Statement

The Extreme 2 series is engineered to be competitive in emerging markets outside of the U.S. where market forces dictate a more aggressive approach. Despite this, Cooler Master includes higher quality capacitors and other critical components. We also make sure that safety regulations such as UL/TUV/ NEMKO/FCC are met and major protections are covered which include: OVP/SCP/OTP/OCP. On top of this, Cooler Master offers a 3-year manufacturer’s warranty.

Safety Regulations

The power supply is required to be tested and to comply with the most current version of the following regulatory specification requirements and/or standards:

Product Safety

Electromagnetic Compatibility

Full Major Protections

Originally at http://www.hardwaresecrets.com/article/Cooler-Master-Extreme-2-475-W-Power-Supply-Review/1550


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