Enermax Platimax 850 W Power Supply Review
By Gabriel Torres on February 16, 2012


Introduction

The 80 Plus Platinum certification is the next level in energy efficiency, promising 92% minimum efficiency at typical load (i.e., at half of the power supply’s labeled power). The Enermax Platimax was one of the first power supply series carrying this new certification level to reach the market, with 600 W, 750 W, 850 W, 1,000 W, and 1,200 W versions. We’ve already tested the 600 W model, which proved to be an excellent product. Let’s see if the 850 W version is a good choice.

Enermax Platimax 850 W power supply
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Figure 1: Enermax Platimax 850 W power supply

Enermax Platimax 850 W power supply
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Figure 2: Enermax Platimax 850 W power supply

The Enermax Platimax 850 W is 6.9” (175 mm) deep, using a 140 mm twister bearing fan on its bottom (Enermax EA142512M-0A).

This unit has a modular cabling system with eight connectors, three for video cards (red) and five for SATA and peripheral power connectors (black). It is really important to understand that each red connector has separate pins for two power cables, so each connector acts as if it were two separate connectors. The motherboard cables and two cables with one six/eight-pin connector for video cards each come permanently attached to the power supply, and they are protected with nylon sleeves that come from inside the unit. This power supply comes with the following cables:

All wires are 18 AWG, which is the minimum recommended gauge, except the main motherboard cable, which uses thicker 16 AWG wires.

The cable configuration is outstanding for an 850 W power supply, allowing you to install three high-end video cards that require two power connectors each at the same time without the need for adaptors, and with 12 SATA power connectors. Since there will be one red connector left unused on the modular cabling system, you can buy an additional cable to install a fourth high-end video card.

Enermax Platimax 850 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 Enermax Platimax 850 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.

Enermax Platimax 850 W power supply
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Figure 4: Top view

Enermax Platimax 850 W power supply
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Figure 5: Front quarter view

Enermax Platimax 850 W power supply
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Figure 6: Rear quarter view

Enermax Platimax 850 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 this stage, this power supply has all required components.

Enermax Platimax 850 W power supply
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Figure 8: Transient filtering stage (part 1)

Enermax Platimax 850 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 Enermax Platimax 850 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Enermax Platimax 850 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one LL25XB60 rectifying bridge, which is attached to an individual heatsink. This bridge supports up to 25 A at 113° C, so in theory, you would be able to pull up to 2,875 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 2,300 W without burning itself out (or 2,587.5 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. This is the same bridge used by the 600 W model.

Enermax Platimax 850 W power supply
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Figure 10: Rectifying bridge

The active PFC circuit uses three TK20J60U MOSFETs, each one supporting up to 20 A at 25° C or 40 A at 25° C in pulse mode. Unfortunately, the manufacturer doesn’t state  the current limit at 100° C. These transistors present a 165 mΩ 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. This configuration is different from the one used in the 600 W model, which has two different transistors.

Enermax Platimax 850 W power supply
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Figure 11: The active PFC transistors and diode

The active PFC is managed by a CM6502S active PFC controller.

Enermax Platimax 850 W power supply
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Figure 12: Active PFC controller

The output of the active PFC circuit is filtered by two 390 µF x 400 V electrolytic capacitors connected in parallel. (This configuration is equivalent of one 780 µF x 400 V capacitor.) These capacitors are Japanese, from Matsushita (Panasonic), labeled at 105° C. The 600 W model uses only one capacitor here.

In the switching section, another two TK20J60U MOSFETs are employed using a resonant configuration. The specifications for these transistors were already discussed above. The transistors used in the 600 W model are different.

Enermax Platimax 850 W power supply
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Figure 13: The switching transistors

The switching transistors are controlled by a CM6901 resonant controller.

Enermax Platimax 850 W power supply
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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 Enermax Platimax 850 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 six IPP015N04N G MOSFETs, each one supporting up to 120 A at 100° C in continuous mode, or 400 A at 25° C in pulse mode, with an RDS(on) of only 1.5 mΩ. The 600 W model uses four 80 A transistors here.

Enermax Platimax 850 W power supply
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Figure 15: +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters. Each is located on two small daughterboards soldered to the main printed circuit board. In Figures 16 and 17, you can see the physical aspect of one of these converters. They are controlled by an APW7073 integrated circuit, using three APM2556NU MOSFETs, each supporting up to 160 A at 25° C or 90 A at 100° C in continuous mode, up to 60 A at 25° C or 48 A at 100° C in pulse mode, and 7.5 mΩ RDS(on). These converters are identical to the ones used in the 600 W model.

Enermax Platimax 850 W power supply
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Figure 16: One of the DC-DC converters

Enermax Platimax 850 W power supply
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Figure 17: One of the DC-DC converters

This power supply uses a PS232S monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections, with four +12 V channels, correctly matching the number of +12 V rails announced by the manufacturer.

Enermax Platimax 850 W power supply
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Figure 18: Monitoring circuit

The electrolytic capacitors that filter the +12 V output are also Japanese, from Chemi-Con, and are labeled at 105° C, as usual. Some solid capacitors are also used.

Power Distribution

In Figure 19, you can see the power supply label containing all the power specs.

Enermax Platimax 850 W power supply
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Figure 19: Power supply label

This power supply is advertised as having four +12 V rails, which is correct, since the monitoring integrated circuit has four +12 V over current (OCP) channels, and we clearly saw four current sensors (“shunts”) on the solder side of the printed circuit board. See Figure 20. Click here to understand more about this subject.

Enermax Platimax 850 W power supply
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Figure 20: Shunts

The four +12 V rails are distributed as follows:

For a better load distribution, we recommend that you do not use the red connector that is connected to the +12V4 rail.

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.” 

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 input was connected to the power supply +12V1, +12V2, +12V3, and +12V4 rails, while the +12VB input was connected to the power supply +12V4 rail.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

6 A (72 W)

13 A (156 W)

19 A (228 W)

25.5 A (306 W)

32.5 A (390 W)

+12VB

6 A (72 W)

13 A (156 W)

19 A (228 W)

25.5 A (306 W)

32 A (384 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 A (5 W)

1.5 A (7.5 W)

2 A (10 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

165.1 W

340.6 W

505.6 W

676.0 W

850.3 W

% Max Load

19.4%

40.1%

59.5%

79.5%

100.0%

Room Temp.

46.0° C

45.8° C

45.8° C

46.8° C

47.4° C

PSU Temp.

47.1° C

47.7° C

45.8° C

49.8° C

50.3° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

183.6 W

371.5 W

555.2 W

756.0 W

969.0 W

Efficiency

89.9%

91.7%

91.1%

89.4%

87.8%

AC Voltage

118.2 V

116.4 V

114.3 V

112.2 V

109.6 V

Power Factor

0.970

0.981

0.988

0.993

0.995

Final Result

Pass

Pass

Pass

Pass

Pass

The Enermax Platimax 850 W passed our tests.

As expected, efficiency was very high, between 87.8% and 91.7% during our tests. The 80 Plus Platinum certification promises minimum efficiency of 90% at light load (i.e., 20% load), 92% at typical load (i.e., 50% load), and 89% at full load. This power supply presented efficiency a hair below these numbers during our tests. Having this occur during our tests is normal, since the 80 Plus certification tests are conducted at 23° C, and we test power supplies between 45° C and 50° C; efficiency drops with higher temperature. Also, the power grid voltage dropped to 107 V during test five, which also affected the results. (Efficiency also drops with the AC voltage.)

Voltages were closer to their nominal values (3% regulation) during all tests, except during test five, when the +3.3 V and +5VSB outputs were below this tighter range, at +3.18 V and +4.81 V, respectively, but still inside the allowed margin. 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.

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 Enermax Platimax 850 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

18.0 mV

22.0 mV

33.6 mV

28.4 mV

33.0 mV

+12VB

18.4 mV

21.2 mV

34.4 mV

26.8 mV

29.6 mV

+5 V

7.4 mV

8.6 mV

10.8 mV

13.2 mV

17.2 mV

+3.3 V

8.6 mV

10.4 mV

11.8 mV

16.4 mV

21.2 mV

+5VSB

10.8 mV

13.8 mV

15.2 mV

18.2 mV

19.8 mV

-12 V

17.6 mV

15.4 mV

22.0 mV

27.6 mV

34.4 mV

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

Enermax Platimax 850 W power supply
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Figure 21: +12VA input from load tester during test five at 850.3 W (33.0 mV)

Enermax Platimax 850 W power supply
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Figure 22: +12VB input from load tester during test five at 850.3 W (29.6 mV)

Enermax Platimax 850 W power supply
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Figure 23: +5V rail during test five at 850.3 W (17.2 mV)

Enermax Platimax 850 W power supply
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Figure 24: +3.3 V rail during test five at 850.3 W (21.2 mV)

Let’s see if we can pull more than 850 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, as we couldn’t pull more than shown in the table below because the power supply would shut down, showing that its protections are present and working fine. During this extreme configuration, noise and ripple levels were still very low, but voltages at the +3.3 V and +5VSB outputs dropped below the minimum allowed, at +3.08 V and +4.72 V, respectively.

Input

Overload Test

+12VA

32.5 A (390 W)

+12VB

32.5 A (390 W)

+5 V

28 A (140 W)

+3.3 V

29 A (92.4 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

994.6 W

% Max Load

117.0%

Room Temp.

46.9° C

PSU Temp.

53.4° C

AC Power

1204 W

Efficiency

82.6%

AC Voltage

107.0 V

Power Factor

0.997

Main Specifications

The main specifications for the Enermax Platimax 850 W power supply include:

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

Conclusions

As expected, the Enermax Platimax 850 W proved to be a top-notch power supply, with outstanding efficiency between 87.8% and 91.7%, voltages closer to their nominal values most of the time, very low noise and ripple levels, and a terrific cable configuration.

The only real negative point of this power supply is its price, USD 250, which is a huge jump from the price of 850 W power supplies with the 80 Plus Gold certification for only two extra percentage points in efficiency. The savvy user will have a far better price/performance ratio buying an 80 Plus Gold power supply instead of the Platimax 850 W, and we have a hard time recommending a USD 250 power supply to anyone. However, if you are the kind of user that only demands “the best” and money isn’t an issue, you will be more than happy with the Enermax Platimax 850 W.

Originally at http://www.hardwaresecrets.com/article/Enermax-Platimax-850-W-Power-Supply-Review/1491


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