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[nextpage title=”Introduction”]

We tested the 450 W version of Thermaltake’s latest entry-level power supply line, Litepower, which promises 85% efficiency. Is that true? Let’s see.

This power supply is also known as W0293RU and is really manufactured by FSP. The marking on the printed circuit board says this power supply is part of the FSPXXX-60GHY series.

Thermaltake Litepower 450 WFigure 1: Thermaltake Litepower 450 W power supply.

Thermaltake Litepower 450 WFigure 2: Thermaltake Litepower 450 W power supply.

Thermaltake Litepower 450 W is a small power supply (5 ½” or 14 cm deep) and has active PFC. As mentioned the manufacturer says it has 85% efficiency and we will test it to see if this is really true or not.

The main motherboard cable uses a 20/24-pin connector, being the only one protected by a nylon sleeving that comes from inside the power supply housing. It comes with only one ATX12V connector, so you can’t use it together with a high-end motherboard that uses an EPS12V connector.

The reviewed power supply comes with only four peripheral cables: one with one six-pin auxiliary power connector for video cards, one with four SATA power connectors, one with three standard peripheral power plugs and one with two standard peripheral power plugs and one floppy disk drive power connector.

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

Even though this power supply presents a satisfactory number of connectors for an entry-level product, it would be better if the manufacturer had divided the four SATA plugs into two separated cables, because the distance between the first and the last connector on the available cable is of only 12” (30 cm) and depending how big is your case and which bay you install your optical unit and your hard drive you may not be able to install them to this cable.

The distance between the power supply housing and the first connector on each cable is of 16 ½” (42 cm), and the distance between each connector on cables that have more than one plug is of only 4” (10 cm).

Thermaltake Litepower 450 WFigure 3: Cables.

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

[nextpage title=”A Look Inside The Litepower 450 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.

Thermaltake Litepower 450 WFigure 4: Overall look.

Thermaltake Litepower 450 WFigure 5: Overall look.

Thermaltake Litepower 450 WFigure 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, yellow component on the pictures below) and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

This stage is flawless, with two coils, one X capacitor (plus one after the rectifying bridges) and two Y capacitors more than needed.

Thermaltake Litepower 450 WFigure 7: Transient filtering stage (part 1).

Thermaltake Litepower 450 WFigure 8: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion about the components used in the Litepower 450 W.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of Litepower 450 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses three US4BK80R rectifying bridges connected in parallel in its primary. This is the first time we’ve seen a power supply using three bridges in parallel. Each one of them can deliver up to 4 A at 125° C if a heatsink is used – which is not the case. Without a heatsink attached, the maximum current drops to practically half of this, 2.1 A at 30° C. Since three of them are used, we have a maximum current of 6.3 A at 30° C. At 115 V this unit would be able to pull up to 725 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 580 W without burning these components. Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply. Why FSP chose to use three bridges without heatsinks instead of just one with a heatsink is a mystery that probably only their accounting department can explain.

Thermaltake Litepower 450 WFigure 9: Rectifying bridges.

On the active PFC circuit two FDPF16N50 power MOSFET transistors are used, each one capable of delivering up to 16 A at 25° C or 9.6 A at 100° C in continuous mode (note the difference temperature makes) or 64 A in pulse mode at 25° C.

Thermaltake Litepower 450 WFigure 10: Active PFC transistors and diode.

The active PFC capacitor is from Teapo and labeled at 85° C.

In the switching section, two FQPF13N50C power MOSFET transistors are used on the traditional two-transistor forward configuration. Each one is capable of delivering up to 13 A at 25° C or 8 A at 100° C in continuous mode (note the difference temperature makes) or 52 A in pulse mode at 25° C.

Thermaltake Litepower 450 WFigure 11: Switching transistors.

The primary is controlled by a CM6805 PWF/PFC combo controller.

[nextpage title=”Secondary Analysis”]

This power supply has seven Schottky rectifiers on its secondary and all are the same model: MBRP3045N, which can deliver up to 30 A (15 A per internal diode at 100° C).

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 three of those rectifiers, so we have a maximum theoretical current of 64 A (15 A x 3 / 0.70), what equals to 771 W.

The +5 V output is produced by two of those rectifiers, giving us a maximum theoretical current of 43 A (15 A x 2 / 0.70), which equals to 214 W.

The +3.3 V output is produced by the other two available rectifiers, giving us a maximum theoretical power of 141 W.

As you can see all outputs are highly overspec’ed, which is always good to see.

Thermaltake Litepower 450 WFigure 12: Secondary rectifiers.

This power supply uses a PS229 monitoring integrated circuit, but specific information about it isn’t available on the manufacturer’s website.

Thermaltake Litepower 450 WFigure 13: Monitoring integrated circuit.

The electrolytic capacitors from the secondary are also from Teapo.

[nextpage title=”Power Distribution”]

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

Thermaltake Litepower 450 WFigure 14: Power supply label.

As you can see this power supply has two +12 V rails, which are distributed like this:

  • +12V1 (solid yellow wire): All cables but the ATX12V.
  • +12V2 (yellow with black stripe wire): ATX12V connector.

We believe this power supply has the correct power distribution, as the CPU (ATX12V) and video card are on separate rails.

Now let’s see if this power supply can really deliver 450 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.

+12V1 and +12V2 are the two independent +12V inputs from our load tester and during our tests the +12V1 input was connected to the power supply +12V1 (main motherboard connector and peripheral power connectors) while the +12V2 input was connected to the power supply +12V2 rail (ATX12V connector).

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12V1 3 A (36 W) 6.5 A (78 W) 9.5 A (114 W) 13 A (156 W) 16 A (192 W)
+12V2 3 A (36 W) 6.5 A (78 W) 9.5 A (114 W) 13 A (156 W) 16 A (192 W)
+5V 1 A (5 W) 2 A (10 W) 4 A (20 W) 5 A (25 W) 6 A (30 W)
+3.3 V 1 A (3.3 W) 2 A (6.6 W) 4 A (13.2 W) 5 A (16.5 W) 6 A (19.8 W)
+5VSB 1 A (5 W) 1 A (5 W) 1 A (5 W) 1.5 A (7.5 W) 2 A (10 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 91.1 W 182.9 W 271.3 W 364.2 W 445.0 W
% Max Load 20.2% 40.6% 60.3% 80.9% 98.9%
Room Temp. 45.5° C 46.3° C 46.5° C 47.0° C 47.4° C
PSU Temp. 46.8° C 47.3° C 47.4° C 47.9° C 48.9° C
Voltage Stability Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power (1) 103 W 203 W 303 W 414 W 517 W
Efficiency (1) 88.4% 90.1% 89.5% 88.0% 86.1%
AC Power (2) 110.4 W 217.0 W 318.2 W 433.7 W 539.5 W
Efficiency (2) 82.5% 84.3% 85.3% 84.0% 82.5%
AC Voltage 112.7 V 111.5 V 110.8 V 109.6 V 108.5 V
Power Factor 0.978 0.964 0.968 0.973 0.976
Final Result Pass Pass Pass Pass Pass

Updated 06/24/2009: We re-tested this power supply using our new GWInstek GPM-8212 power meter, which is a precision instrument and provides accuracy of 0.2% and thus presenting the correct readings for AC power and efficiency (resul
ts marked as "2" on the table above; results marked as "1" were measured with our previous power meter from Brand Electronics, which isn’t so precise as you can see). We also added the numbers for AC voltage during our tests, an important number as efficiency is directly proportional to AC voltage (the higher AC voltage is, the higher efficiency is). Also, manufacturers usually announce efficiency at 230 V, which usually inflates efficiency numbers. We added power factor (PF) numbers as well. These numbers measure the efficiency of the power supply active PFC circuit. This number should be as close to 1 as possible. The active PFC circuit from this unit is good but could be better, because easily see other units with active PFC achieving a power factor of 0.99.

Efficiency was great, especially for an entry-level product: between 84% and 85% if you pull between 40% and 80% from its labeled power (between 180 W and 360 W). Under light load (20% load, i.e., 90 W) and full load (450 W) efficiency was at 82.5%, which is still fair enough.

Electrical noise was always at low levels, between 30.8 mV (test one) and 54.4 mV (test five) on +12V1, between 22.8 mV (test one) and 43.4 mV (test five) on +12V2, between 12.6 mV (test one) and 15.4 mV (test five) on +5 V and between 12.8 mV (test one) and 20.8 mV (test five) on +3.3 V. These numbers are peak-to-peak values and the maximum allowed is of 120 mV on +12 V outputs and 50 mV on +5 V and +3.3 V outputs.

Now let’s see if we could pull more than 450 W from this unit.

[nextpage title=”Overload Tests (Cont’d)”]

Before overloading power supplies we always test first if the over current protection (OCP) circuit is active and at what level it is configured.

In order to do that we configured our load tester with a low (1 A) current on +12V2 and increased current at +12V1 until the power supply shut down. This happened when we tried to pull more than 22 A from +12V1.

Manufacturers always leave a margin between what is written on the label (17 A in this case) and the level the OCP circuit is really configured (22 A in this case). We always like to see this margin as tight as possible.

Then starting from test five we increased currents on +12 V, +5 V and +3.3 V to the maximum we could with the power supply still running inside ATX specs. The results are below. When we tried to increase one more amp at any output ripple would go to the roof, meaning that the unit stopped working correctly.

Input Maximum
+12V1 19.5 A (234 W)
+12V2 19.5 A (234 W)
+5V 9 A (45 W)
+3.3 V 6 A (19.8 W)
+5VSB 2 A (10 W)
-12 V 0.5 A (6 W)
Total 542.9 W
% Max Load 120.6%
Room Temp. 47.4° C
PSU Temp. 48.9° C
AC Power (1) 645 W
Efficiency (1) 84.2%
AC Power (2) 675 W
Efficiency (2) 80.4%
AC Voltage 107.4 V
Power Factor 0.979

Even during this extreme configuration efficiency was above 80%, which is great (consider the results marked as "2", as they are the correct ones, measured with our precision power meter).

[nextpage title=”Main Specifications”]

Thermaltake Litepower 450 W power supply specs include:

  • ATX12V 2.3
  • Nominal labeled power: 450 W.
  • Measured maximum power: 542.9 W at 47.4° C.
  • Labeled efficiency: 85%.
  • Measured efficiency: Between 82.5% and 85.3% at 115 V (nominal, see complete results for actual voltage).
  • Active PFC: Yes.
  • Modular Cabling System: No.
  • Motherboard Power Connectors: One 24-pin connector and one ATX12V connector.
  • Video Card Power Connectors: One six-pin connector.
  • Peripheral Power Connectors: Five in two cables.
  • Floppy Disk Drive Power Connectors: One.
  • SATA Power Connectors: Four in one cable.
  • Protections: Over current (OCP, tested and working), over voltage (OVP, not tested) and short-circuit (SCP, tested and working).
  • Warranty: Five years.
  • More Information: https://www.thermaltakeusa.com
  • Real Manufacturer: FSP
  • Average price in the US*: USD 80.00.

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

[nextpage title=”Conclusions”]

This is an excellent entry-level power supply, with efficiency between 84% and 85% if you pull between 40% and 80% from its maximum load (between 180 W and 360 W). During light load (20% load, i.e., 90 W) and full load (450 W) efficiency was at 82.5%, still above 80% and fair enough for an entry-level product. We wonder why other manufacturers don’t follow Thermaltake’s steps and release really high-efficiency products for this market segment. In other words, why high-efficiency should be only seen on high-end and expensive products?

But of course not everything is perfect, and even Litepower 450 W has its drawbacks, which are the presence of only one ATX12V connector with no EPS12V support and all SATA power cables being located on the same cable, what can make it difficult to install SATA optical drives and SATA hard drives on the same cable, depending on the size of your case and on which bays you decide to install these units.

If these limitations don’t bother you, this is a terrific buy for building a high-efficiency mainstream PC (translation: lower electricity bill compared to PCs built with traditional low-end power supplies).