Thortech Thunderbolt 850 W Power Supply Review
By Gabriel Torres on August 31, 2011


Introduction

Thortech is a power supply brand that belongs to the memory manufacturer, GeIL. So far they have only released units with 80 Plus Gold certification and modular cabling system under two series: Thunderbolt, with 650 W, 850 W, 1,000 W, and 1,200 W versions; and Thunderbolt Plus, with only one model (800 W), which we’ve already reviewed. The only difference between the two series is the presence of a digital power meter on the Thunderbolt Plus model. Let’s see if the Thunderbolt 850 W power supply is a good product.

The power supplies from Thortech are manufactured by Sirfa/Highpower.

Thortech Thunderbolt 850 W power supply
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Figure 1: Thortech Thunderbolt 850 W power supply

Thortech Thunderbolt 850 W power supply
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Figure 2: Thortech Thunderbolt 850 W power supply

The Thortech Thunderbolt 850 W is 6.3” (160 mm) deep, using a 135 mm ball bearing fan on its bottom (Globe Fan RL4Z B1352512H).

This unit has a modular cabling system, with four cables permanently attached to the power supply with nylon sleeves. This power supply comes with the following cables:

All wires are 18 AWG, except the wires on the main motherboard cable, which are 16 AWG (i.e., thicker), which is very nice to see.

The cable configuration is good, with 12 SATA power connectors and an above-the-average distance between connectors. This unit could have six video card power connectors in order to allow the installation of three high-end video cards without the need of power adapters.

Thortech Thunderbolt 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 Thortech Thunderbolt 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.

Thortech Thunderbolt 850 W power supply
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Figure 4: Top view

Thortech Thunderbolt 850 W power supply
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Figure 5: Front quarter view

Thortech Thunderbolt 850 W power supply
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Figure 6: Rear quarter view

Thortech Thunderbolt 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 is flawless, with one X capacitor and two Y capacitors more than the minimum required.

Thortech Thunderbolt 850 W power supply
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Figure 8: Transient filtering stage (part 1)

Thortech Thunderbolt 850 W power supply
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Figure 9: Transient filtering stage (part 2)

In the next page, we will have a more detailed discussion about the components used in the Thortech Thunderbolt 850 W.

Primary Analysis

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

This power supply uses two TS15P05G rectifying bridges, but they aren’t attached to a heatsink. These bridges support up to 15 A at 110° C each, so in theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 2,760 W without burning themselves out. Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.

Thortech Thunderbolt 850 W power supply
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Figure 10: Rectifying bridges

The active PFC circuit uses two SPW24N60C3 MOSFETs, each supporting up to 24.3 A at 25° C or 15.4 A at 100° C in continuous mode (note the difference temperature makes), or 72.9 A at 25° C in pulse mode. These transistors present a 160 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.

Thortech Thunderbolt 850 W power supply
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Figure 11: One of the active PFC transistors

This power supply uses two electrolytic capacitors in parallel to filter the output from the active PFC circuit. The use of two capacitors in parallel divides the current that flows through each one of them, reducing the amount of heat generated. The Thunderbolt 850 W uses one 330 µF x 400 V capacitor connected in parallel; this is equivalent to one 660 µF x 400 V capacitor. These capacitors are Japanese, from Rubycon, and are labeled at 105° C.

In the switching section, another two SPW24N60C3 MOSFETs are used in the traditional two-transistor forward configuration. The specifications for these transistors were already discussed above.

Thortech Thunderbolt 850 W power supply
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Figure 12: Switching transistors

The primary is controlled by the popular CM6800 active PFC/PWM combo controller.

Thortech Thunderbolt 850 W power supply
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Figure 13: Active PFC/PWM combo controller

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

Secondary Analysis

The Thortech Thunderbolt 850 W uses a DC-DC design in its secondary, meaning that this power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs being generated by two smaller switch-mode power supplies connected to the main +12 V output. This design is proving to be the best solution to achieve high efficiency. Also, this unit uses a synchronous design for the +12 V rectification. This means that the rectifying diodes were replaced with transistors in order to increase efficiency.

The +12 V output uses eight AOT480 MOSFETs, each one capable of handling up to 180 A at 25° C or up to 134 A at 100° C in continuous mode, or up to 500 A at 25° C in pulse mode, with an RDS(on) of only 4.5 mΩ. Apparently, three are used for the direct rectification and five are used for the “freewheeling” part of the rectification.

Thortech Thunderbolt 850 W power supply
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Figure 14: The +12 V transistors

The +5 V and +3.3 V outputs are generated by two small power supplies available on small daughterboards attached to the +12 V rail. Each of these power supplies is comprised of four IPD060N03L MOSFETs (50 A at 100° C, 6 mΩ resistance) and one APW7073 PWM controller.

Thortech Thunderbolt 850 W power supply
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Figure 15: One of the DC-DC converters

This power supply uses a PS224 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections. The over current protection circuit available in this integrated circuit has four channels: one for +3.3 V, one for +5 V, and two for +12 V. This power supply, however, is sold as having four +12 V rails. We will talk more about the real rail configuration of this power supply in the next page.

Thortech Thunderbolt 850 W power supply
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Figure 16: Monitoring circuit

The electrolytic capacitors that filter the +5 V and +3.3 V rails are solid, while the capacitors that filter the +12 V rails are Japanese, from Chemi-Con.

Power Distribution

In Figure 17, you can see the power supply label containing all the power specs.

Thortech Thunderbolt 850 W power supply
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Figure 17: Power supply label

This power supply is sold as having four +12 V rails, and we could clearly see four current sensors (“shunts”) on the solder side of the printed circuit board. For the untrained eye, this would be the proof that this unit has four +12 V rails. However, taking a closer look at these current sensors, we can clearly see that they are connected in parallel, resulting in this unit having a single +12 V rail design. They would need to be connected exclusively to a unique group of wires to be monitoring that specific group of wires and, therefore, creating a “rail.” Another proof that this power supply doesn’t have four +12 V rails is that there are no wires connected to the hole labeled +12V2 on the printed circuit board. Click here to learn more about this subject.

Thortech Thunderbolt 850 W power supply
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Figure 18: Current sensors (“shunts”) are connected in parallel

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, both inputs were connected to the power supply’s single +12 V rail.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

6 A (72 W)

13 A (156 W)

18.5 A (222 W)

25 A (300 W)

31 A (372 W)

+12VB

6 A (72 W)

13 A (156 W)

18.5 A (222 W)

25 A (300 W)

31 A (372 W)

+5 V

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

173.4 W

348.1 W

508.6 W

678.4 W

850.2 W

% Max Load

20.4%

41.0%

59.8%

79.8%

100.0%

Room Temp.

44.8° C

44.8° C

45.8° C

47.9° C

49.5° C

PSU Temp.

39.8° C

41.3° C

42.6° C

44.1° C

47.9° C

Voltage Regulation

Pass

Pass

Pass

Pass

Failed at +3.3 V

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

195.1 W

385.6 W

568.6 W

769.0 W

985.0 W

Efficiency

88.9%

90.3%

89.4%

88.2%

86.3%

AC Voltage

113.6 V

111.8 V

110.3 V

107.6 V

104.4 V

Power Factor

0.921

0.972

0.985

0.991

0.994

Final Result

Pass

Pass

Pass

Pass

Fail

The Thortech Thunderbolt 850 W can really deliver its labeled wattage at high temperatures.

Efficiency was between 88.2% and 90.3% when we pulled between 20% and 80% of the unit’s labeled power (i.e., between 170 W and 680 W). At full load (850 W), efficiency was at 86.3%, just a tiny bit below the 87% required by the 80 Plus Gold certification. However, the 80 Plus certification tests are conducted at a room temperature of only 23° C, and efficiency drops as temperature increases.

Voltages were closer to their nominal values (3% regulation) during all tests, except for the -12 V output during test one, and the +3.3 V output during tests three (at +3.19 V), four (at +3.14 V), and five (at +3.09 V). Unfortunately, the +3.3 V output dropped below the minimum required (+3.135 V) during test five. The ATX12V specification says 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 Thortech Thunderbolt 850 W provided really 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

30.0 mV

35.6 mV

40.6 mV

47.4 mV

54.4 mV

+12VB

27.4 mV

31.8 mV

33.8 mV

38.2 mV

45.2 mV

+5 V

10.2 mV

10.8 mV

11.4 mV

12.8 mV

15.2 mV

+3.3 V

12.4 mV

13.4 mV

14.6 mV

15.4 mV

19.2 mV

+5VSB

11.2 mV

11.4 mV

11.6 mV

11.8 mV

14.4 mV

-12 V

41.2 mV

47.4 mV

52.2 mV

57.6 mV

63.4 mV

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

Thortech Thunderbolt 850 W power supply
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Figure 19: +12VA input from load tester during test five at 850.2 W (54.4 mV)

Thortech Thunderbolt 850 W power supply
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Figure 20: +12VB input from load tester during test five at 850.2 W (45.2 mV)

Thortech Thunderbolt 850 W power supply
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Figure 21: +5V rail during test five at 850.2 W (15.2 mV)

Thortech Thunderbolt 850 W power supply
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Figure 22: +3.3 V rail during test five at 850.2 W (19.2 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. We couldn’t pull more than that because we reached the limit of our load tester. This unit may be able to deliver even more power. During this test, the +3.3 V output dropped even further, to +3.00 V. All other voltages were still inside the tighter 3% range, and ripple and noise levels were still low.

Input

Overload Test

+12VA

33 A (396 W)

+12VB

33 A (396 W)

+5 V

23 A (115 W)

+3.3 V

23 A (75.9 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

990.4 W

% Max Load

116.5%

Room Temp.

46.9° C

PSU Temp.

47.9° C

AC Power

1,174.4 W

Efficiency

84.3%

AC Voltage

103.1 V

Power Factor

0.995

Main Specifications

The main specifications for the Thortech Thunderbolt 850 W power supply include:

Conclusions

The Thortech Thunderbolt 850 W can really deliver its labeled power at high temperatures, provides high efficiency between 86.3% and 90.3%, and has very low ripple and noise levels. The cable configuration is very good, with 12 SATA power connectors with an above-the-average distance between them.

The main problem with the reviewed unit is its +3.3 V output, which dropped below the minimum allowed at 850 W. (Interestingly, Jonnyguru.com saw a similar problem with the 1,200 W version of this unit, probably indicating that this is a design flaw.)

Originally at http://www.hardwaresecrets.com/article/Thortech-Thunderbolt-850-W-Power-Supply-Review/1372


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