Thermaltake Toughpower XT 775 W Power Supply Review
By Gabriel Torres on February 16, 2010
Thermaltake is adding four new models to their Toughpower XT series, 575 W, 675 W, 775 W and 875 W. The first question that came into our minds was “do they use a different internal design”? This question is important since we tested the 750 W version of Toughpower XT and it presented a very high noise level at +12 V output when delivering its labeled wattage. Let’s see if things improved with the 775 W model.
The answer was “yes.” While the other members of Toughpower XT series use the traditional PC power supply design, these new members are based on a DC-DC design (where basically the power supply is a +12 V unit with the +5 V and +3.3 V outputs being produced from the +12 V rail), which usually provides higher efficiency and lower noise levels. So although they use the same name, the design is completely different.
Like the original Toughpower series, Toughpower XT is manufactured by CWT. Since some power supplies from Corsair like HX750W and HX850W are also manufactured by CWT and also use a DC-DC design, the first thing we did was to compare these power supplies to see if they were based on the same project. The answer is negative: this product from Thermaltake is different from these products from Corsair.
Like the other members from Toughpower XT series, these new models have a set of three LEDs that gives you basic status about the power supply working conditions. The "old" versions from Toughpower XT have 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). On the new models the fan will keep spinning for 30 seconds after you turn them off, but the 15/30-second configuration switch was removed. All Toughpower XT units use of a single-rail design, while the original Toughpower series uses a four-rail design.
Officially Toughpower XT 775 W is 80 Plus Silver certified, but Thermaltake decided to downgrade it to Bronze. This is not the first time we’ve seen a manufacturer doing this when they feel that at higher temperatures efficiency would drop to the point that the unit wouldn’t be able to achieve the same efficiency as announced by 80 Plus – especially because 80 Plus certification is done at 23° C and Thermaltake guarantees that Toughpower XT 775 W can deliver its labeled power at 50° C 24/7.
The previous version of Toughpower XT is available in two options: standard and cable management, which features a modular cabling system. The new models have all a modular cabling system, with no option for not having this feature.
Toughpower XT 775 W is relatively short for a product on this power range, being 6 1/4” (160 mm) deep. It has a 140 mm fan on its bottom, active PFC, single-rail design and modular cabling system.
Two cables are permanently attached to the power supply (the main motherboard cable and the ATX12V/EPS12V cable) and they feature a nylon protection, but the sleevings don’t come from inside the power supply, as you can see in Figure 2. The modular cabling system has eight connectors, four blacks for SATA/peripherals power cables and four dark red for video card power cables.
The cables included on Toughpower XT 775 W are:
This is a satisfactory number of connectors for a power supply on this range. In fact a flaw from the 750 W version was corrected on this version: on the 750 W version two of the video card power cables use an eight-pin connector without the option to convert them to six-pin models, preventing you from installing two high-end video cards that require two six-pin connectors each, like the GeForce GTX 260 and similar cards.
All cables use 18 AWG wires, which is the correct gauge to be used.
Now let’s take an in-depth look inside this power supply.
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. As mentioned, this unit is completely different from Toughpower XT 750 W.
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, one extra coil and one X capacitor after the rectification bridges. The MOV is behind the fuse and can’t be seen in Figure 8.
In the next page we will have a more detailed discussion about the components used in the Thermaltake Toughpower XT 775 W.
On this page we will take an in-depth look at the primary stage of Thermaltake Toughpower XT 775 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses two GBU806 rectifying bridges connected in parallel in its primary. Each one supports up to 8 A at 100° C if a heatsink is used, which is the case (without a heatsink the limit drops to 3.5 A also at 100° C). So in theory you would be able to pull up to 1,840 W from the power grid; assuming 80% efficiency, the bridges would allow this unit to deliver up to 1,472 W without burning themselves 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.
The electrolytic capacitor in charge of filtering the output from the active PFC circuit is Japanese from Chemi-Con and rated at 85° C.
In the switching section, two IRFP460A power MOSFET transistors are used in the traditional two-transistor forward configuration, each one capable of delivering up to 20 A at 25° C or up to 13 A at 100° C in continuous mode, or up to 80 A at 25° C in pulse mode, presenting an RDS(on) of 270 mΩ.
This power supply uses the omnipresent CM6800 active PFC/PWM combo controller.
Now let’s take a look at the secondary of this power supply.
The secondary from the new Toughpower XT models is different in two aspects. First, as mentioned, it uses a DC-DC design, meaning that the power supply is basically a +12 V unit with the +5 V and +3.3 V outputs being produced by two small switching power supplies attached to the +12 V output. And the main +12 V rail uses a synchronous design, name given when the rectifiers are replaced with MOSFET transistors in order to increase efficiency.
Five IPP057N08N3 power MOSFET are used on the main +12 V rail, three in charge of the direct rectification and two in charge of the “freewheeling” part of the rectification. Each transistor can deliver up to 80 A at 100° C in continuous mode, or up to 320 A at 25° C in pulse mode, with an RDS(on) of 5.4 mΩ, which is extremely low (which is great, the lower this number, the higher efficiency is).
The +5 V and +3.3 V outputs are produced by two small printed circuit boards that are attached to the main +12 V rail. Each board features a small switch-mode power supply based on an APW7073 PWM controller and four ME90N03 MOSFETs, each one capable of handling up to 60 A at 25° C or 47 A at 70° C in continuous mode, or up to 240 A at 25° C in pulse mode, with a maximum RDS(on) of 9 mΩ. Each board has five solid caps.
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.
Electrolytic capacitors from the secondary are Taiwanese from Teapo. Unfortunately Thermaltake says that this unit has “Japanese capacitors” (plural), which isn’t true; only the main electrolytic capacitor from the primary is Japanese. We’ve seen this happen before on some Seventeam power supplies and the problem was the translation from Chinese to English.
In Figure 17, you can see the power supply label containing all the power specs.
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 775 W.
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 and during all test both were connected to the single +12 V rail present on the power supply.
5 A (60 W)
11 A (132 W)
16 A (192 W)
22 A (264 W)
28 A (336 W)
5 A (60 W)
10 A (120 W)
16 A (192 W)
21 A (252 W)
28 A (336 W)
2 A (10 W)
4 A (20 W)
6 A (30 W)
8 A (40 W)
10 A (50 W)
2 A (6.6 W)
4 A (13.2 W)
6 A (19.8 W)
8 A (26.4 W)
10 A (33 W)
1 A (5 W)
1.5 A (7.5 W)
2 A (10 W)
2.5 A (12.5 W)
3 A (15 W)
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)
% Max Load
Ripple and Noise
The new Toughpower XT 775 W presents an excellent efficiency across the board, but in particular between 310 W and 620 W, where we saw efficiency between 85.6% and 87.3%, which is of course better numbers than the ones presented by the “old” Toughpower XT 750 W model.
As mentioned, Ecos Consulting gave this unit the 80 Plus Silver certification (85% minimum at 20% and 100% loads and 88% minimum at 50% load), but Thermaltake decided to downgrade it to Bronze (82% minimum at 20% and 100% loads and 85% minimum at 50% load). This was a very smart move and Thermaltake deserve our sincere compliments for that, since at higher temperatures this unit can’t present the same efficiency performance as it presented at Ecos Consulting lab (at 23° C).
All outputs were with their voltages within the expected range (+12 V and +5 V always within a tighter 3% range; +3.3 V didn’t want to stay within this tighter range but was still within the allowed 5% tolerance).
But what really improved on this new Toughpower XT was noise and ripple levels. See below the results achieved on test 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.
Now let’s see if we can pull more power from this unit.
Below you can see the maximum we could pull from Thermaltake Toughpower 775 W. If we tried to pull more than that the unit would shut down.
33 A (396 W)
33 A (396 W)
15 A (75 W)
15 A (49.5 W)
3 A (15 W)
0.5 A (6 W)
% Max Load
Thermaltake Toughpower XT 775 W power supply specs include:
The new Toughpower XT models (575 W, 675 W, 775 W and 875 W) have absolutely nothing to do with the previous Toughpower and Toughpower XT units, as they use a completely different internal design (synchronous design with DC-DC converters). This allowed the 775 W unit to achieve a higher efficiency and lower noise levels compared to the “old” 750 W model from the XT series. Another thing that Thermaltake fixed was the video card cables, as the 750 W model has two eight-pin connectors, preventing you from installing two video cards that require two six-pin connectors each (e.g., GeForce GTX 260) at the same time.
This power supply should be arriving in the US market very soon. Thermaltake is announcing it as having a USD 170 MSRP, but we know that power supplies are rarely sold by their suggested prices, most stores offer them for less.
It will probably arrive on the USD 150 range, where it will meet the fierce competition from Corsair HX750W, SilverStone Strider Plus 750 W and the new 750 W model from XFX (that we still have to review). This model from Corsair has as advantage offering higher efficiency, while the reviewed model from Thermaltake has a higher labeled wattage – however both units could easily deliver above 900 W in our tests. And the model from SilverStone has a similar performance at a lower price (USD 130).
Thermaltake Toughpower XT 775 W is definitely a good power supply that easily beats cheaper 750 W units (Seventeam ST-750P-AF, Cooler Master GX 750 W, Thermaltake TR2 RX 750 W, etc), but its success among its competitors will depend a lot on its street price.