Enermax MODU87+ 700 W Power Supply Review
By Gabriel Torres on January 12, 2010


Introduction

Hardware Secrets Golden Award

Enermax MODU87+ is the 80 Plus Gold certified series from Enermax, meaning efficiency of at least 90% at typical load (350 W in the case of the reviewed 700 W model) and 87% at light (140 W in the case of the reviewed 700 W model) and full loads. Let’s dissect the 700 W model from this new series.

MODU87+ series will have models from 500 W to 900 W, but only the 600 W and the 700 W models are being launched this month; the other models will be launched on the following months. Like other series from Enermax, the name MODU87+ means that this series has a modular cabling system. Enermax will also release PRO87+ series with power supplies internally identical to the ones from the MODU87+ series, but without a modular cabling system.

Enermax MODU87+ 700 W power supply
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Figure 1: Enermax MODU87+ 700 W power supply.

Enermax MODU87+ 700 W power supply
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Figure 2: Enermax MODU87+ 700 W power supply.

Enermax MODU87+ 700 W is 6 19/64” (160 mm) deep, using a 140 mm magnetic bearing fan on its bottom and active PFC circuit, of course.

The reviewed power supply features a modular cabling system with seven connectors, with three cables permanently attached to the power supply. These cables have nylon sleevings that come from inside the power supply unit.

The cables included are:

This configuration is good enough for a 700 W product, providing four connectors for video cards, allowing you to connect two video cards that require two power connectors each.

Enermax MODU87+ 700 W power supply
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Figure 3: Cables.

The main motherboard cable uses thicker 16 AWG wires, which is terrific, while all other cables use 18 AWG wires, which is the minimum recommended.

Now let’s take an in-depth look inside this power supply.

A Look Inside The Enermax MODU87+ 700 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.

This page will be an overview, and then in the following pages we will discuss in detail the quality and ratings of the components used.

Enermax MODU87+ 700 W power supply
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Figure 4: Overall look.

Enermax MODU87+ 700 W power supply
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Figure 5: Overall look.

Enermax MODU87+ 700 W power supply
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Figure 6: Overall look.

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. 

This power supply is flawless on this stage, with two Y capacitors and one ferrite coil more than the minimum required, plus one X capacitor after the rectifying bridge.

Enermax MODU87+ 700 W power supply
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Figure 7: Transient filtering stage (part 1).

Enermax MODU87+ 700 W power supply
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Figure 8: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion about the components used in the Enermax MODU87+ 700 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of Enermax MODU87+ 700 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU2006 rectifying bridge in its primary, which can deliver up to 20 A at 100° C if a heatsink is used, which is the case. At 115 V this unit would be able to pull up to 2,300 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,840 W without burning this component. That is what we call overspecification! Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Enermax MODU87+ 700 W power supply
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Figure 9: Rectifying bridge.

On the active PFC circuit two TK20J60T power MOSFET transistors are used, each one capable of delivering up to 20 A at 25° C (unfortunately the manufacturer doesn’t say the limit at 100° C) in continuous mode, or up to 40 A in pulse mode at 25° C. These transistors present a resistance of 165 mΩ when turned on, a characteristic called RDS(on). This number indicates the amount of power that is wasted, so the lower this number the better, as less power will be wasted thus increasing efficiency.

Enermax MODU87+ 700 W power supply
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Figure 10: Active PFC transistors and diode.

The active PFC circuit is controlled by a CM6502 PFC controller.

Enermax MODU87+ 700 W power supply
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Figure 11: Active PFC controller.

This power supply uses a Japanese capacitor from Rubycon labeled at 85° C to filter the output from the active PFC circuit. For a “Gold” power supply we expected to see a 105° C capacitor here.

In the switching section, two SiHG20N50C power MOSFET transistors are used. Each of the transistors is capable of delivering up to 20 A at 25° C or 11 A at 100° C in continuous mode, or up to 80 A at 25° C in pulse mode, with an RDS(on) of 225 mΩ.

Enermax MODU87+ 700 W power supply
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Figure 12: Switching transistors.

The switching transistors are connected using a design called “LLC resonant,” also known as a series parallel resonant converter, being controlled by a CM6901 integrated circuit, which operates under PWM (Pulse Width Modulation) mode when the power supply is operating under light load but under FM (Frequency Modulation) mode under other loads. This is the same design on the other 80 Plus Gold power supply we’ve reviewed, Seasonic X-Series 650 W.

Enermax MODU87+ 700 W power supply
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Figure 13: Controller.

Now let’s take a look at the secondary of this power supply.

Secondary Analysis

This power supply uses a DC-DC converter design on the secondary, meaning that this is basically a +12 V power supply where the +5 V and +3.3 V outputs are produced by two separated power supplies connected to the +12 V line. This design is proving to be the best solution for achieving high efficiency. On top of that the +12 V power supply uses a synchronous design. On this kind of design the rectifiers are replaced by transistors (MOSFETs) for higher efficiency.

The +12 V output is produced by four IRFB3206 MOSFETs, two for the direct rectification and two for the “freewheeling” part of the rectification. Each transistor has a maximum RDS(on) of only 2.5 mΩ and can deliver up to 270 A at 25° C or up to 190 A at 100° C in continuous mode, or up to 1,080 A at 25° C in pulse mode. Good Lord! This would give us a maximum theoretical current of 266 A for the whole +12 V bus; if all this current would be pulled from the +12 V outputs, this unit would be able to deliver up to 3,192 W! Of course other parts of this power supply would burn way before we could be even close to this theoretical value. MODU87+ definitely gives “overspecification” a total new meaning!

Enermax MODU87+ 700 W power supply
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Figure 14: +12 V transistors (the diode on the right is used for the +5VSB output).

A unique feature from MODU87+ 700 W is the configuration of the filtering stage of the +12 V line. It uses a mix of solid capacitors and Japanese caps from Chemi-Con installed on small printed circuit boards attached to the main power supply board, plus a very high-end filtering coil.

Enermax MODU87+ 700 W power supply
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Figure 15: Configuration of the filtering capacitors.

The +5 V and +3.3 V outputs are produced by two separated DC-DC modules, which are connected to the main +12 V line to produce these two voltages. Each module uses three APM2556 MOSFETs, controlled by an APW7073 integrated circuit, and only solid caps.

Enermax MODU87+ 700 W power supply
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Figure 16: One of the DC-DC modules.

Enermax MODU87+ 700 W power supply
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Figure 17: One of the DC-DC modules.

The outputs are monitored by a PS231 integrated circuit, plus an LM339 voltage comparator is also used.

Enermax MODU87+ 700 W power supply
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Figure 18: Monitoring integrated circuit.

Power Distribution

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

Enermax MODU87+ 700 W power supply
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Figure 19: Power supply label.

As you can see, according to the label this unit has three +12 V rails. These rails are distributed like this:

This distribution is perfect, as keep the CPU (through the ATX12V/EPS12V connectors) and the video cards in separated rails.

One interesting thing: each red connector from the modular cabling system, which is used to connect the video card power cable, is half connected to the +12V2 rail and half connected to the +12V3 rail. Since each cable has two connectors, this means that each connector from the same cable is connected to separated rails. Thus when using two video cards that require only one power connector each, the best deal is to use only one cable, this way you are ensuring that one of the video cards is installed on +12V2 and the other one is installed on +12V3. If you use the two cables you may end up connecting the two video cards to the same rail.

Now let’s see if this power supply can really deliver 700 W.

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 how the reviewed unit behaved 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 power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (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. On 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 and +12V3 rails, while the +12VB input was connected to the power supply +12V1 rail.

Note: We are now using the names +12VA and +12VB for the two inputs from our load tester because some people were thinking that the “+12V1” and “+12V2” names present on our table referred to the power supply rails, which is not the case.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

5 A (60 W)

10 A (120 W)

15 A (180 W)

20 A (240 W)

25 A (300 W)

+12VB

5 A (60 W)

10 A (120 W)

15 A (180 W)

20 A (240 W)

25 A (300 W)

+5V

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

10 A (50 W)

+3.3 V

2 A (6.6 W)

4 A (13.2 W)

6 A (30 W)

8 A (26.4 W)

10 A (33 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

150.2 W

290.0 W

429.8 W

567.9 W

704.6 W

% Max Load

21.5%

41.4%

61.4%

81.1%

100.7%

Room Temp.

45.2° C

44.3° C

44.4° C

46.6° C

48.0° C

PSU Temp.

53.2° C

53.2° C

53.9° C

55.4° C

57.3° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

166.8 W

320.5 W

482.3 W

647.0 W

818.0 W

Efficiency

90.0%

90.5%

89.1%

87.8%

86.1%

AC Voltage

117.2 V

116.1 V

114.6 V

112.8 V

110.0 V

Power Factor

0.973

0.986

0.994

0.996

0.997

Final Result

Pass

Pass

Pass

Pass

Pass

Enermax MODU87+ 700 W can really deliver its labeled wattage at high temperatures.

Efficiency was always very high, around 90% when we pulled between 20% and 40% from the unit’s maximum labeled capacity (i.e., between 140 W and 280 W). At 60% load (420 W) efficiency was still extremely high at 89.1%, dropping to 87.8% at 80% load (560 W) and to 86.1% at 100% load (700 W).

In theory this unit would need to present 87% efficiency at full load in order to qualify for the 80 Plus Gold certification, but keep in mind that this organization tests power supplies at a room temperature of 25° C while we test units between 45° C and 50° C and the higher the temperature, the lower efficiency is.

Voltages were always inside the allowed range.

Noise and ripple levels were another highlight from this product, being always low. Below you can see these levels with the power supply delivering 705 W (test five). The maximum allowed is 120 mV for the +12 V output and 50 mV for the +5 V and +3.3 V outputs. All numbers are peak-to-peak figures.

Enermax MODU87+ 700 W power supply
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Figure 20: +12VA input from load tester at 704.6 W (53.4 mV).

Enermax MODU87+ 700 W power supply
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Figure 21: +12VB input from load tester at 704.6 W (52.4 mV).

Enermax MODU87+ 700 W power supply
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Figure 22: +5V rail with power supply delivering 704.6 W (23.6 mV).

Enermax MODU87+ 700 W power supply
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Figure 23: +3.3 V rail with power supply delivering 704.6 W (35.6 mV).

When we tried to pull more than 700 W from this unit it would shut down. This was probably due to some sort of limitation from our equipment, since a friend of ours could pull up to 1,000 W from this unit.

Main Specifications

Enermax MODU87+ 700 W power supply specs include:

Conclusions

Enermax MODU87+ 700 W is a terrific power supply, achieving very high efficiency between 86% and 90.5%. Voltages were always inside the required range with low noise and ripple. The protections are clearly active. And the cable configuration is perfect for a 700 W product. For the user looking for “the best” 700 W unit around and price isn’t a concern, the new Enermax MODU87+ 700 W is certainly the best pick.

The problem with this unit is its price, far away from the average user level. It will come with a suggested price of USD 219, but most on-line stores will be selling for less.

Compared to the other 80 Plus Gold that we’ve already reviewed, Seasonic X-Series 650 W, this new unit from Enermax achieved a little bit better efficiency under light load, while this model from Seasonic achieved a little bit better efficiency under full load.

Originally at http://www.hardwaresecrets.com/article/Enermax-MODU87+-700-W-Power-Supply-Review/900


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