SilverStone Strider Plus 750 W Power Supply Review
By Gabriel Torres on January 25, 2010


Introduction

Hardware Secrets Golden Award

SilverStone released a new power supply series with full modular cabling system, 80 Plus Silver certification and single +12 V rail, called Strider Plus, with 750 W, 850 W and 1,000 W models. Let’s test the 750 W model.

The new Strider Plus series is manufactured by Enhance Electronics. Please keep in mind that other power supply series from SilverStone are manufactured by different companies.

SilverStone Strider Plus 750 W power supply
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Figure 1: SilverStone Strider Plus 750 W power supply.

SilverStone Strider Plus 750 W power supply
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Figure 2: SilverStone Strider Plus 750 W power supply.

SilverStone Strider Plus 750 W isn’t a deep power supply, especially for a unit with a full modular cabling system, being 6 19/64” (160 mm) long, using a 135 mm fan on its bottom and active PFC circuit, of course.

The reviewed power supply features a full modular cabling system, which means that even the main motherboard cable is part of the modular system. The modular cabling system has 11 connectors, four blue ones for the video card power cables, two 4-pin black ones for the CPU power cables, four 3-pin black ones for the SATA and peripheral power cables and one 24-pin one for the main motherboard cable.

One great thing about the cables from SilverStone Strider Plus 750 W is that the wires from the video card auxiliary power cables and ATX12V/EPS12V – plus the +12 V (yellow) wires from the main motherboard cable – are 16 AWG, i.e., thicker than required, which is great. All other wires are 18 AWG, which is the minimum required gauge to be used.

The cables included are:

Strider Plus 750 W comes with a good cable configuration for a 750 W product, although we’d prefer if this unit came with one more SATA cable. The highlight of this product is the good distance between the SATA and peripheral connectors, which are 4” (10 cm) more distant to each other than usual.

SilverStone Strider Plus 750 W power supply
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Figure 3: Cables.

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

A Look Inside The SilverStone Strider Plus 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.

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. At a first glance the printed circuit board from SilverStone Strider Plus 750 W looks like the printed board from Zalman ZM-770XT. However, after a closer look, we could see that SilverStone Strider Plus 750 W has two coils on its secondary, while Zalman ZM-770XT has three.

SilverStone Strider Plus 750 W power supply
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Figure 4: Overall look.

SilverStone Strider Plus 750 W power supply
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Figure 5: Overall look.

SilverStone Strider Plus 750 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 two X capacitors more than the minimum required, plus an X capacitor and two Y capacitors after the rectifying bridge.

SilverStone Strider Plus 750 W power supply
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Figure 7: Transient filtering stage (part 1).

SilverStone Strider Plus 750 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 SilverStone Strider Plus 750 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of SilverStone Strider Plus 750 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU1006 rectifying bridge in its primary, capable of delivering up to 10 A at 100° C. At 115 V this unit would be able to pull up to 1,150 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply. Interesting enough Zalman ZM-770XT, which is based on a similar project, has two of these bridges connected in parallel.

SilverStone Strider Plus 750 W power supply
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Figure 9: Rectifying bridge.

On the active PFC circuit two STW25NM50N power MOSFET transistors are used, each one capable of delivering up to 22 A at 25° C or 14 A at 100° C in continuous mode (note the difference temperature makes), or up to 88 A in pulse mode at 25° C. These transistors present a resistance of 140 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. Zalman ZM-770XT uses more powerful transistors here (32 A,  20 A and 96 A, respectively).

This power supply uses two electrolytic capacitors to filter the output from the active PFC circuit. The use of more than one capacitor here has absolute nothing to do with the “quality” of the power supply, as laypersons may assume (including people without the proper background in electronics doing power supply reviews around the web). Instead of using one big capacitor, manufacturers may choose to use two or more smaller components that will give the same total capacitance, in order to better accommodate space on the printed circuit board, as two or more capacitors with small capacitance are physically smaller than one capacitor with the same total capacitance. SilverStone Strider Plus 750 W uses two 270 µF x 420 V capacitors in parallel; this is equivalent of one 540 µF x 420 V capacitor. These capacitors are Japanese, from Chemi-Con and labeled at 85° C. These are the same components used on Zalman ZM-770XT.

In the switching section, two STW25NM50N power MOSFET transistors are used, using the traditional two-transistor forward design. Each one is capable of delivering up to 22 A at 25° C or 14 A at 100° C in continuous mode, or up to 88 A at 25° C in pulse mode, with an RDS(on) of 140 mΩ. These are the same transistors used on Zalman ZM-770XT.

SilverStone Strider Plus 750 W power supply
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Figure 10: Switching transistors, active PFC diode and active PFC transistors.

The primary is controlled by the popular CM6802 PWM/PFC combo integrated circuit. Interesting enough Zalman ZM-770XT is controlled by the previous version from this chip, CM6800.

SilverStone Strider Plus 750 W power supply
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Figure 11: PWM/PFC combo controller.

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

Secondary Analysis

This power supply uses a synchronous design on its +12 V output. This means that the rectifiers were replaced with MOSFETs for higher efficiency. The +5 V and +3.3 V outputs still use the traditional design using Schottky rectifiers. Therefore, the design from SilverStone Strider Plus 750 W is somewhat different from the design from Zalman ZM-770XT, even thought visually the two power supplies look alike.

The maximum theoretical current 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. Just as an exercise, we can assume a typical duty cycle of 30%.

The +12 V output is produced by four IRFB3207 power MOSFETs, each one supporting up to 180 A at 25° or up to 130 A at 100° C in continuous mode, or up to 720 A at 25° C in pulse mode. Wow. This gives us a maximum theoretical current of 371 A or 4,457 W for the +12 V output. Of course the practical limit will depend on other components.

The +5 V output is produced by one STPS40L45CW Schottky rectifier, which supports up to 40 A (20 A per internal diode at 130° C, 0.40 V maximum voltage drop). This gives us a maximum theoretical current of 29 A or 143 W.

The +3.3 V output is produced by another STPS40L45CW Schottky rectifier, giving us a maximum theoretical current of 29 A or 94 W.

All these numbers are theoretical. The real amount of current/power each output can deliver is limited by other components, especially by the coils used on each output.

SilverStone Strider Plus 750 W power supply
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Figure 12: +12 V transistors, +5 V and +3.3 V rectifiers, and +5VSB diode.

The outputs are monitored by a PS232 integrated circuit, which supports the following protections: over current (OCP), under voltage (UVP) and over voltage (OVP). Any other protection that this unit may have is implemented outside this integrated circuit.

SilverStone Strider Plus 750 W power supply
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Figure 13: Monitoring circuit.

Electrolytic capacitors from the secondary are from Teapo and labeled at 105° C.

Power Distribution

In Figure 14, you can see the power supply label containing all the power specs.

SilverStone Strider Plus 750 W power supply
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Figure 14: Power supply label.

This power supply has a single-rail design, so there is not much to talk about here.

Now let’s see if this power supply can really deliver 750 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 both inputs were connected to the power supply single rail (+12VB input was connected to the power supply EPS12V connector and all other cables were connected to the load tester +12VA input).

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)

11 A (132 W)

16 A (192 W)

22 A (264 W)

27 A (324 W)

+12VB

5 A (60 W)

10 A (120 W)

16 A (192 W)

21 A (252 W)

27 A (324 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 (19.8 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

147.4 W

297.5 W

446.6 W

594.6 W

741.3 W

% Max Load

19.7%

39.7%

59.5%

79.3%

98.8%

Room Temp.

46.0° C

44.6° C

45.2° C

46.6° C

47.9° C

PSU Temp.

53.0° C

52.2° C

52.6° C

53.8° C

55.7° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

174.6 W

342.5 W

514.7 W

699.0 W

895.0 W

Efficiency

84.4%

86.9%

86.8%

85.1%

82.8%

AC Voltage

114.8 V

112.9 V

111.1 V

109.1 V

106.6 V

Power Factor

0.972

0.989

0.994

0.995

0.995

Final Result

Pass

Pass

Pass

Pass

Pass

SilverStone Strider Plus 750 W can really deliver its labeled wattage at high temperatures.

Efficiency was very high when we pulled up to 80% of the unit’s maximum capacity (i.e., up to 600 W), between 84.4% and 86.9%. At full load (750 W) efficiency was still good at 82.8%. Since this unit is 80 Plus Silver certified, it should present 85% efficiency under full and light (20%) loads and 88% under typical (50% load). As we already explained on our Can We Trust the 80 Plus Certification? article, 80 Plus certification process is conducted at a room temperature of 25° C, while we test power supplies between 45° C and 50° C, and efficiency drops with temperature. Therefore if we were in charge of the 80 Plus certification process, this unit would be an 80 Plus Bronze, not Silver.

Voltage regulation was the highlight from this power supply. All voltages (except -12 V) stayed at a maximum of 3% from their nominal values (i.e., voltages closer to their official values than required, since the ATX specification allows them to be up to 5% from their nominal values (10% for the -12 V).

Noise and ripple were low at all times. Below you can see the results for test five, with the power supply delivering around 740 W. The maximum allowed values are 120 mV for the +12 V outputs and 50 mV for the +5 V and +3.3 V outputs, peak-to-peak figures.

SilverStone Strider Plus 750 W power supply
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Figure 15: +12VA input from load tester at 741.3 W (32.6 mV).

SilverStone Strider Plus 750 W power supply
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Figure 16: +12VB input from load tester at 741.3 W (41.4 mV).

SilverStone Strider Plus 750 W power supply
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Figure 17: +5V rail with power supply delivering 741.3 W (19.8 mV).

SilverStone Strider Plus 750 W power supply
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Figure 18: +3.3 V rail with power supply delivering 741.3 W (20.2 mV).

Let’s see if we can pull more power from SilverStone Strider Plus 750 W.

Overload Tests

When we tried to overload SilverStone Strider Plus 750 W after running test number five, the unit would shut down and not turn back on, showing that the over temperature protection was in action (inside the unit we saw two thermal sensors, so it really has OTP). So we had to let the power supply completely cool down so we could see the maximum this unit could deliver. The maximum we could reach with the reviewed unit is listed below. Above that one of the protections would enter in action, shutting down the unit.

Input

Maximum

+12VA

32 A (384 W)

+12VB

32 A (384 W)

+5V

10 A (50 W)

+3.3 V

10 A (33 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

848.2 W

% Max Load

113.1%

Room Temp.

38.5° C

PSU Temp.

37.3° C

AC Power

1,046 W

Efficiency

81.1%

AC Voltage

104.4 V

Power Factor

0.998

Main Specifications

SilverStone Strider Plus 750 W power supply specs include:

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

Conclusions

SilverStone Strider Plus 750 W is very good power supply, being offered with a fair price tag for its performance and features, and therefore we are giving it our Golden Award.

Efficiency is one of its highlights, peaking 86.9% in our tests. Voltage regulation was superb, with its main outputs always within 3% of their nominal values (i.e., voltages closer to their standard values than required). And noise and ripple was always relatively low.

The cable configuration is good for a 750 W product, with four individual cables for video cards, but we’d like it better if it presented three more SATA power cables. Another good thing about the cable configuration from this unit is that SATA and peripheral connectors are 9 7/8” (25 cm) apart from each other, which is 4” (10 cm) more than the norm.

And of course its fully modular cabling system is a must and will please all users.

SilverStone Strider Plus 750 W is way better than the overpriced Zalman ZM-770XT, even though they are manufactured by the same company (Enhanced Electronics). This model from Zalman offers only two video card cables and lower performance. The higher performance from Strider Plus 750 W was achieved by using a synchronous design of the secondary (translation: rectifiers were replaced with MOSFET transistors for higher efficiency).

Originally at http://www.hardwaresecrets.com/article/SilverStone-Strider-Plus-750-W-Power-Supply-Review/911


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