Thermaltake Toughpower XT 750 W Power Supply Review
By Gabriel Torres on July 30, 2009


Introduction

Hardware Secrets Silver Award

Toughpower XT is an updated version of the famous Toughpower series from Thermaltake, featuring two novelties. First, a set of three LEDs that gives you basic status about the power supply working conditions. Second, a switch where you can configure the power supply fan to keep spinning for 15 or 30 seconds after you turn off your PC, which in theory can increase the product life-span. Another difference is the use of a single-rail design, while the original Toughpower series uses a four-rail design. Let’s test the 750 W model and see if it is a good buy.

Like the original Toughpower series, Toughpower XT is manufactured by CWT. Since we have already disassembled the original Toughpower 750 W unit, we will be able to do a detailed comparison between the designs used on these two units.

It is important to note that even though this power supply is manufactured by CWT like Corsair HX750W they use a complete different design. Toughpower XT 750 W uses the traditional PC power supply design, while Corsair HX750W uses a DC-DC design on the secondary, which proved to provide superior efficiency.

Toughpower XT 750 W is 80 Plus Bronze certified, meaning a minimum efficiency of 85% at typical load (50% load, i.e., 375 W) and a minimum efficiency of 82% under light (20% load, i.e., 150 W) and full (750 W) loads.

Toughpower XT units are available in two versions: standard and cable management, which features a modular cabling system. We reviewed a sample from the standard version.

Thermaltake Toughpower XT 750W power supply
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Figure 1: Thermaltake Toughpower XT 750W power supply.

Thermaltake Toughpower XT 750W power supply
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Figure 2: Thermaltake Toughpower XT 750W power supply.

Toughpower XT 750 W is relatively short for a 750 W product, being 6 19/64” (160 mm) deep. It has a 140 mm fan on its bottom, active PFC, single-rail design (the original Toughpower has four rails) and optional modular cabling system (available on the “cable management” models).

In Figure 3, you can see the switch available on the rear from the unit where you can configure the fan to keep spinning after the computer is turned off. Three positions are available: “auto,” “15 seconds” and “30 seconds.”

Thermaltake Toughpower XT 750W power supply
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Figure 3: Fan delay control.

Toughpower XT has a set of three LEDs that monitor the standby (+5VSB) voltage, the power good signal and the over temperature protection, see Figure 4.

Thermaltake Toughpower XT 750W power supply
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Figure 4: Status LEDs.

All cables have a nylon protection, but the sleevings don’t come from inside the power supply, as you can see in Figure 2. The cables included on Toughpower XT 750 W are:

There is a big problem here: two of the video card power cables use an eight-pin connector without the option to convert them to six-pin models. This prevents you from installing two high-end video cards that require two six-pin connectors each, like the GeForce GTX 260 and similar cards. Thermaltake should have used six/eight-pin connectors.

The number of peripheral cables is terrific, but we think this unit could have more SATA power connectors.

All cables use 18 AWG wires, which is the correct gauge to be used.

Thermaltake Toughpower XT 750W power supply
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Figure 5: Cables.

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

A Look Inside The Toughpower XT 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. The first thing that caught our attention was that the printed circuit board from Toughpower XT 750 W has practically the same layout from Toughpower 750 W, even thought the heatsinks are different.

Thermaltake Toughpower XT 750W power supply
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Figure 6: Overall look.

Thermaltake Toughpower XT 750W power supply
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Figure 7: Overall look.

Thermaltake Toughpower XT 750W power supply
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Figure 8: 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 has all required components plus one extra X capacitor, four extra Y capacitors and one extra coil. The MOV can be seen between the fuse and the first coil in Figure 10, using a black rubber protection. This stage is identical from Toughpower 750 W. Notice how the X capacitor in Figure 10 brings the “PSH-750” marking on it, indicating CWT’s original model.

Thermaltake Toughpower XT 750W power supply
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Figure 9: Transient filtering stage (part 1).

Thermaltake Toughpower XT 750W power supply
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Figure 10: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion about the components used in the Thermaltake Toughpower XT 750 W.

Primary Analysis

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

This power supply uses one GBJ1506 rectifying bridge in its primary (the same one used on Toughpower 750 W), supporting up to 15 A at 100° C, so in theory, you would be able to pull up to 1,725 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 W without burning itself out. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Two SPW20N60C3 power MOSFETs are used on the active PFC circuit, each one capable of delivering up to 20.7 A at 25° C or 13.1 A at 100° C in continuous mode (note the difference temperature makes) or up to 62.1 A at 25° C in pulse mode. These transistors present a maximum resistance of 190 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. These are the same transistors used on Toughpower 750 W.

Thermaltake Toughpower XT 750W power supply
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Figure 11: Rectifying bridge and active PFC transistors.

The electrolytic capacitor in charge of filtering the output from the active PFC circuit is Japanese from Hitachi and rated at 85° C. This is exactly the same capacitor used on Toughpower 750 W.

In the switching section, another two SPW20N60C3 power MOSFET transistors are used. These are the same transistors used on Toughpower 750 W.

Thermaltake Toughpower XT 750W power supply
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Figure 12: Switching transistors.

This power supply uses a CM6802 active PFC/PWM combo controller. Here is the main difference between the primary from Toughpower 750 W and from the new Toughpower XT 750 W. The previous model used a CM6800 controller. The difference between the two is the efficiency goal: CM6800 targets 80% efficiency, while CM6802 targets 82% efficiency.

Thermaltake Toughpower XT 750W power supply
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Figure 13: Active PFC/PWM combo controller.

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

Secondary Analysis

The secondary from Toughpower XT 750 W is different from the original Toughpower 750 W, however. Toughpower XT 750 W uses six Schottky rectifiers on its secondary, while the original Toughpower 750 W uses only four. The secondary from Toughpower XT 750 W provides a higher maximum theoretical current/power than the original Toughpower 750 W.

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 STPS40L45CT Schottky rectifiers, each one supporting up to 40 A (20 A per internal diode at 130° C with a maximum voltage drop of 0.49 V). From the eight diodes available, three are used for the direct rectification and the other five are used for the “freewheeling” part of the rectification (i.e., discharge the coil). This gives us a maximum theoretical current of 86 A or 1,029 W for the +12 V output.

The +5 V output is produced by one STPS60L30CW Schottky rectifier, capable of handling up to 60 A (30 A per internal diode at 130° C, maximum voltage drop of 0.38 V). This gives us a maximum theoretical current of 43 A or 214 W for the +5 V output.

The +3.3 V output is produced by another STPS60L30CW Schottky rectifier. This gives us a maximum theoretical current of 43 A or 141 W for the +3.3 V output.

Thermaltake Toughpower XT 750W power supply
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Figure 14: Rectifiers.

This power supply uses a PS229 monitoring integrated circuit, which is in charge of the power supply protections. Unfortunately there is no information about this circuit on the manufacturer’s website.

Thermaltake Toughpower XT 750W power supply
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Figure 15: Monitoring circuit.

Electrolytic capacitors from the secondary are also Japanese, from Chemi-Con and labeled at 105° C. This is an improvement over the original Toughpower, which uses Chinese caps.

Power Distribution

In Figure 16, you can see the power supply label containing all the power specs.

Thermaltake Toughpower XT 750W power supply
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Figure 16: Power supply label.

This power supply uses a single-rail design, so there is nothing to talk about here. Keep in mind that the difference between a single-rail design and a multiple-rail design is how the over current protection (OCP) circuit is connected. On single-rail design there is only one OCP circuit monitoring all outputs, while on multiple-rail design there are several OCP circuits, each one monitoring a group of wires called “rails.”

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 +12V1 and +12V2 inputs listed below are the two +12 V independent inputs from our load tester and during all test both were connected to the single +12 V rail present on the power supply.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12V1

5 A (60 W)

11 A (132 W)

16 A (192 W)

22 A (264 W)

27 A (324 W)

+12V2

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

147.8 W

298.9 W

447.8 W

596.7 W

744.9 W

% Max Load

19.7%

39.9%

59.7%

79.6%

99.3%

Room Temp.

47.3° C

49.5° C

48.8° C

49.5° C

48.7° C

PSU Temp.

46.0° C

49.9° C

52.1° C

54.8° C

53.9° C

Voltage Stability

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Failed on +12V2

AC Power

175.7 W

348.1 W

528.7 W

718.0 W

932.0 W

Efficiency

84.1%

85.9%

84.7%

83.1%

79.9%

AC Voltage

114.1 V

113.1 V

110.7 V

108.1 V

104.6 V

Power Factor

0.978

0.986

0.993

0.996

0.997

Final Result

Pass

Pass

Pass

Pass

Fail

Toughpower XT 750 W presents an excellent efficiency between 84% and 86% if you pull up to 60% from its labeled capacity, i.e., up to 450 W. Pulling 80% from its maximum load (i.e., 600 W) efficiency was still good at 83%. But at full load (750 W) efficiency dropped to 80%.

You have to keep in mind that the 80 Plus organization measures efficiency at a room temperature of only 23° C, which is impossible to achieve inside a PC. We test power supplies at a room temperature at least double that and we consider our results to be more realistic. Since efficiency drops with temperature, usually our numbers are lower than the ones achieved by 80 Plus.

Voltage stability was the highlight from Toughpower XT 750 W. All outputs (including -12 V) were within 3% from their nominal values. Translation: they were closer to their nominal values than allowed by the ATX specification, which sets a 5% margin (10% for -12 V).

Noise and ripple were the problem on Toughpower XT 750 W. While ripple and noise levels were in all tests within admissible range on +5 V and +3.3 V outputs, they reached and passed the 120 mV limit on +12 V output during test number five, when the unit was delivering 750 W. During test four noise and ripple at +12 V were around 100 mV and during test three they were around 70 mV.

Below you can see the results for test number five. As we always point out, the limits are 120 mV for +12 V and 50 mV for +5 V and +3.3 V and all numbers are peak-to-peak figures.

Thermaltake Toughpower XT 750W power supply
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Figure 17: +12V1 input from load tester at 744.9 W (115.4 mV).

Thermaltake Toughpower XT 750W power supply
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Figure 18: +12V2 input from load tester at 744.9 W (130.6 mV).

Thermaltake Toughpower XT 750W power supply
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Figure 19: +5V rail with power supply delivering 744.9 W (17.4 mV).

Thermaltake Toughpower XT 750W power supply
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Figure 20: +3.3 V rail with power supply delivering 744.9 W (16.4 mV).

Since this unit was running already outside ATX specs during test number five, we decided not to publish our traditional overload tests. When we tried to overload this unit, it kept shutting down after a while, showing that one of its protections entered in action. The idea behind of overload tests is to see if the power supply will burn/explode and see if the protections from the power supply are working correctly. This power supply didn’t burn or explode and it shut down when we tried to overload it.

Main Specifications

Thermaltake Toughpower XT 750 W power supply specs include:

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

Conclusions

Thermaltake Toughpower XT 750 W is based on the same basic project as the original Toughpower 750 W, but modified in order for the power supply to achieve higher efficiency: the reviewed unit presents an excellent efficiency between 84% and 86% if you pull up to 60% from its labeled capacity, i.e., up to 450 W. Pulling 80% from its maximum load (i.e., 600 W) efficiency was still good at 83%. But at full load (750 W) efficiency dropped to 80%.

You have to keep in mind that the 80 Plus organization measures efficiency at a room temperature of only 23° C, which is impossible to achieve inside a PC. We test power supplies at a room temperature at least double that and we consider our results to be more realistic. Since efficiency drops with temperature, usually our numbers are lower than the ones achieved by 80 Plus.

Voltage stability was the highlight from Toughpower XT 750 W. All outputs (including -12 V) were within 3% from their nominal values. Translation: they were closer to their nominal values than allowed by the ATX specification, which sets a 5% margin (10% for -12 V).

Available with or without cabling management system, it competes directly with Seventeam ST-750Z-AF (modular cabling system) and ST-750P-AF (no modular cabling system), Corsair TX750W and several other units. Toughpower XT 750 W has as advantages a little bit higher efficiency, which is always great, a higher number of power connectors, the status LEDs and the fan delay control.  On the other hand we have the problem with ripple and noise, which on Toughpower XT 750 W were higher than the maximum allowed when the unit was delivering 750 W. It is important to keep in mind that this won’t be a problem for most users, as even fully loaded PCs won’t pull even close to 750 W.

You should pay attention on price. For some strange reason Newegg.com is offering today the model with modular cabling system for USD 130 (the right price for this product, in our opinion) and the model without modular cabling for USD 170, which doesn’t make sense, as for this price we can buy products such as Corsair HX750W and Seasonic M12D 750 W, which are far superior products.

Toughpower XT 750 W is certainly an option if you are looking for a power supply up to USD 130.

We are giving it our “Silver Award” instead of our “Golden Award” because of the high ripple and noise levels measured during our tests.

Originally at http://www.hardwaresecrets.com/article/Thermaltake-Toughpower-XT-750-W-Power-Supply-Review/776


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