Thermaltake TR2 RX 750 W Power Supply Review

[nextpage title=”Introduction”]

TR2 is a cost-effective power supply series from Thermaltake, which is comprised of two sub-series: TR2 standard (430 W, 500 W, 600 W, 700 W and 1,000 W) and TR2 RX (450 W, 550 W, 650 W, 750 W, 850 W, 1,000 W and 1,200 W). Models from TR2 RX series have modular cabling system. Being targeted to users on budget, several model from this series don’t even have the standard 80 Plus certification. Today we are going to test the 750 W from TR2 RX series. Is it a good buy? Let’s see.

Figure 1: Thermaltake TR2 RX 750 W power supply.

Figure 2: Thermaltake TR2 RX 750 W power supply.

Thermaltake TR2 RX 750 W is 6 19/64” (160 mm) deep, using a 140 mm fan on its bottom and active PFC circuit, of course.

The reviewed power supply features a modular cabling system with six connectors (two red for video cards and four black for peripheral and SATA connectors), with four cables permanently attached to the power supply. These cables have nylon sleevings that come from inside the power supply unit.

The cables included are:

• Main motherboard cable with a 24-pin connector (no 20-pin option, permanently attached to the power supply).
• One cable with two ATX12V connectors that together form one EPS12V connector (permanently attached to the power supply).
• Two cables with one six-pin connector for video cards each (one permanently attached to the power supply and one available through the modular cabling system).
• Two cables with one six/eight pin connector for video cards each (one permanently attached to the power supply and one available through the modular cabling system).
• One SATA power cable with four SATA power connectors (modular cabling system).
• One SATA power cable with three SATA power connectors (modular cabling system).
• Two peripheral power cables with three standard peripheral connectors and one floppy disk drive power connector each (modular cabling system).

This configuration is good enough for a 750 W product, providing four connectors for video cards, allowing you to connect two video cards that require two power connectors each.

Figure 3: Cables.

The cables that are permanently attached to the unit are 22” (56 cm) long, while the ones from the modular cabling system are 19 ¾” (50 cm) long up to the first connector and then 5 7/8” (15 cm) between connectors.

All cables use 18 AWG wires, which is the minimum recommended, but the main motherboard cable uses thicker 16 AWG wires for the +3.3 V output, which is great.

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

[nextpage title=”A Look Inside The Thermaltake TR2 RX 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.

Figure 4: Overall look.

 Figure 5: Overall look.

 Figure 6: Overall look.

[nextpage title=”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, two X capacitors and one ferrite coil more than the minimum required.

Figure 7: Transient filtering stage (part 1).

Figure 8: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion about the components used in the Thermaltake TR2 RX 750 W.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of Thermaltake TR2 RX 750 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 supporting up to 8 A at 100° C. At 115 V this unit 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. Nice overspecification! Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply.

On the active PFC circuit three SPP20N60C3 power MOSFET transistors are used, 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 in pulse mode at 25° C. These transistors present a 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.

Figure 9: Active PFC diode, active PFC transistors and rectification bridges.

This power supply uses a capacitor from Su’scon labeled at 85° C to filter the output from the active PFC circuit.

In the switching section, another two SPP20N60C3 power MOSFETs are used on the traditional two-transistor forward configuration. The specs for these transistors are published above.

Figure 10: Switching transistors.

The switching transistors are controlled by the famous PFC/PWM combo controller CM6800.

Figure 11: PFC/PWM controller.

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

[nextpage title=”Secondary Analysis”]

This power supply has eight Schottky rectifiers on its secondary.

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 SBR30A50CT Schottky rectifiers, each one supporting up to 30 A (15 A per internal diode at 110° C, 0.55 V maximum voltage drop), giving us a maximum theoretical current of 86 A or 1,029 W for the +12 V output.

The +5 V output is produced by two SBR30A40CT Schottky rectifiers, each one supporting up to 30 A (15 A per internal diode at 110° C, 0.50 V maximum voltage drop), giving us a maximum theoretical current of 43 A or 214 W.

The +3.3 V output is produced by another two SBR30A40CT Schottky rectifiers, giving us a maximum theoretical current of 43 A or 141 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.

Figure 12: +3.3 V, +5 V and +12 V rectifiers.

The outputs are monitored by a PS223 integrated circuit, which supports OCP (over current protection), OVP (over voltage protection), UVP (under voltage protection) and OTP (over temperature protection, not implemented on this power supply)

Figure 13: Monitoring integrated circuit.

[nextpage title=”Power Distribution”]

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

Figure 14: Power supply label.

As you can see, according to the label this unit has a single +12 V rail, so there is not much to talk about here.

Now let’s see if this power supply can really deliver 750 W.

[nextpage title=”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 (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	146.4 W	306.4 W	440.9 W	583.9 W	Fail
% Max Load	19.5%	40.9%	58.8%	77.9%	Fail
Room Temp.	45.0° C	45.6° C	47.6° C	45.6° C	Fail
PSU Temp.	55.9° C	55.5° C	56.1° C	55.2° C	Fail
Voltage Regulation	Pass	Pass	Pass	Pass	Fail
Ripple and Noise	Pass	Pass	Pass	Fail on +12 V	Fail on +12 V
AC Power	169.5 W	355.5 W	521.8 W	713.0 W	Fail
Efficiency	86.4%	86.2%	84.5%	81.9%	Fail
AC Voltage	115.9 V	113.9 V	112.6 V	110.9 V	Fail
Power Factor	0.994	0.972	0.981	0.988	Fail
Final Result	Pass	Pass	Pass	Fail	Fail

According to our methodology, Thermaltake TR2 RX 750 W cannot deliver its labeled wattage. It burned after one minute delivering 750 W at a room temperature a little bit above 45° C. Thinking that we may have got a defective unit, we asked Thermaltake another sample, which burned exactly the same way. In both units the component that burned was one of the +12 V rectifiers.

Efficiency was always high when we pulled up to 60% of the power supply maximum load (i.e., up to 450 W), between 84.5% and 86.4%. But at 80% load (600 W) efficiency dropped to 81.9%, still above the 80% mark. At full load we couldn’t measure efficiency, because the unit burned before we could read all numbers.

Not being able to deliver its labeled wattage is not the worst about this power supply. Noise and ripple levels were way above the maximum allowed during tests four and five. With the first sample, noise levels during test four was 130.2 mV at +12VA and 127.6 mV at +12VB, jumping to 183.8 mV and 166.8 mV during test five, respectively. We got even worse results with the second sample, as it also failed on +5 V and +3.3 V, as we summarize in the table below. The maximum allowed is 120 mV on +12 V and 50 mV on +5 V and +3.3 V. All these numbers are peak-to-peak figures. Below we show the scope waveforms for you to see the problem.

Input	Test 4	Test 5
+12VA	154.4 mV	197.4 mV
+12VB	155.2 mV	195.5 mV
+5 V	45.6 mV	54.6 mV
+3.3 V	39.6 mV	54.8 mV

Figure 15: +12VA input from load tester during test five with the first sample (154.4 mV).

Figure 16: +12VB input from load tester during test five with the first sample (155.2 mV).

Figure 17: +5V rail during test five with the first sample (45.6 mV).

[nextpage title=”Main Specifications”]

Thermaltake TR2 RX 750 Wpower supply specs include:

• ATX12V 2.3
• EPS12V 2.91
• Nominal labeled power: 750 W at 40° C.
• Measured maximum power: 583.9 W at 45.6° C.
• Labeled efficiency: 86% minimum (80 Plus certified)
• Measured efficiency: Between 81.9% and 86.4% at 115 V (nominal, see complete results for actual voltage).
• Active PFC: Yes.
• Modular Cabling System: Yes, partial.
• Motherboard Power Connectors: One 24-pin connector and two ATX12V connectors that together form an EPS12V connector (permanently attached to the power supply).
• Video Card Power Connectors: Two six-pin connectors and two six/eight pin connectors, all using individual cables (two permanently attached to the power supply, two using the modular cabling system).
• SATA Power Connectors: Seven in two cables (modular cabling system).
• Peripheral Power Connectors: Six in two cables (modular cabling system).
• Floppy Disk Drive Power Connectors: Two in two cables (modular cabling system).
• Protections: Over voltage (OVP, not tested), over current (OCP, not tested) and short-circuit protection (SCP, tested and working).
• Warranty: Five years
• More Information: https://www.thermaltakeusa.com
• Average price in the US: USD 95.00

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

[nextpage title=”Conclusions”]

Thermaltake TR2 RX 750 W is, according to our methodology, a flawed product that must be avoided at all costs. It can’t deliver its labeled wattage at high temperatures, but this is not the worst of it: ripple and noise level are way above the maximum allowed when you pull 80% or more from the unit’s labeled capacity (i.e., 600 W and above), overloading your components (especially electrolytic capacitors from the motherboard and video cards), which can cause your PC to present an erratic behavior (crashes and random resets) and, under extreme conditions, damage components.