Introduction

XFX, a traditional video card manufacturer, has recently decided to enter the power supply business. They first offering, an 850 W model called Black Edition proved to be an outstanding product. Now they are launching a more mainstream model rated at 650 W, called XXX Edition, featuring modular cabling system, single-rail design and 80 Plus Bronze certification. Will this model live up to the expectation? Let’s see.

This power supply is manufactured by Seasonic.

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Figure 1: XFX 650 W XXX Edition power supply.

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Figure 2: XFX 650 W XXX Edition power supply.

XFX 650 W XXX Edition 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 eight connectors, but some of the cables are 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 20/24-pin connector (21 5/8” or 55 cm, permanently attached to the power supply).
• One cable with two ATX12V connectors that together form one EPS12V connector (21 5/8” or 55 cm, permanently attached to the power supply).
• One cable with one EPS12V connector (21 5/8” or 55 cm, permanently attached to the power supply).
• One auxiliary power cable for video cards with one six-pin connector (21 5/8” or 55 cm, permanently attached to the power supply).
• One auxiliary power cable for video cards with one six/eight-pin connector (23 5/8” or 60 cm, permanently attached to the power supply).
• Two auxiliary power cables for video cards with one six/eight-pin connector each (21 5/8” or 55 cm, modular cabling system).
• Two SATA power cables with three SATA power connectors each (19 ¾” or 50 cm to the first connector, 5 7/8” or 15 cm between connectors, modular cabling system).
• Two peripheral power cables with three standard peripheral power plugs and one floppy disk drive power connector each (19 ¾” or 50 cm to the first connector, 5 7/8” or 15 cm between connectors, modular cabling system).

This configuration is perfect for a 650 W product, providing four connectors for video cards, allowing you to connect two video cards that require two power connectors each.

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Figure 3: Cables.

Although all wires are 18 AWG (the correct gauge to be used), inside the power supply pairs of +12 V (yellow) wires are joined into a single wire, which is not good. The same happens with ground (black) wires.

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

A Look Inside The XFX 650 W XXX Edition

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, while in the following pages we will discuss the quality and ratings of the components used in detail. Here we had a déjà vu feeling. Looking further we discovered why: this is a Silencer power supply from PC Power & Cooling (see Figures 7 and 8), using the same printed circuit board from Silencer 610 EPS12V we’ve already reviewed. The difference, of course, is that PC Power & Cooling does not offer products with a modular cabling system. So XFX and PC Power & Cooling use the same OEM: Seasonic.

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Figure 4: Overall look.

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Figure 5: Overall look.

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Figure 6: Overall look.

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Figure 7: The name “SILENCER” was blacked out but it is still clearly visible.

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Figure 8: PC Power & Cooling name.

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, one X capacitor and one ferrite coil more than the minimum required, plus one X capacitor after the rectifying bridge.

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Figure 9: Transient filtering stage (part 1).

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Figure 10: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion of the components used in the XFX 650 W XXX Edition.

Primary Analysis

On this page we will take an in-depth look at the primary stage of XFX 650 W XXX Edition. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBJ1506 rectifying bridge in its primary, which can deliver up to 15 A at 100º C if a heatsink is used, which is the case (without a heatsink the limit drops to 3 A at 25º C). At 115 V this unit 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 this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply. This is the same bridge used on Silencer 610 EPS12V from PC Power & Cooling, which this unit is derived from.

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Figure 11: Rectifying bridge.

On the active PFC circuit two SPP24N60C3 power MOSFET transistors are used, each one capable of delivering up to 24.3 A at 25º C or 15.3 A at 100º C in continuous mode (note the difference temperature makes), or up to 72.9 A in pulse mode at 25º C. These transistors present a resistance of 160 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 transistors are more powerful than the ones used on Silencer 610 EPS12V from PC Power & Cooling (20.7 A, 13.1 A and 62.1 A, respectively).

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Figure 12: Active PFC transistors, active PFC diode and switching transistors.

This power supply uses a Japanese capacitor from Chemi-Con labeled at 105º C to filter the output from the active PFC circuit, which is excellent (Japanese capacitors are better and being labeled at 105º C is better than being labeled at 85º C).

In the switching section, two FDP18N50 power MOSFET transistors are used, connected on the traditional two-transistor forward configuration. Each of the transistors is capable of delivering up to 18 A at 25º C or 10.8 A at 100º C in continuous mode, or up to 72 A at 25º C in pulse mode, with an RDS(on) of 265 mΩ. Silencer 610 EPS12V use different transistors here (FQP18N50V2), which has a higher continuous current at 100º C (12.1 A).

The primary is controlled by a PFC/PWM combo integrated circuit, a UCC28515DW, which is exactly the same circuit used on Silencer 610 EPS12V from PC Power & Cooling.

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Figure 13: PFC/PWM combo controller.

In summary, the primary from XFX 650 W XXX Edition is similar to the one from PC Power & Cooling 610 EPS12V, with the unit from XFX using more powerful transistors on the active PFC circuit and the model from PC Power & Cooling using transistors on the switching section with a little bit higher current specs.

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

Secondary Analysis

This power supply has four Schottky rectifiers attached to the secondary heatsink, plus a 7805 voltage regulator that is used for the +5VSB output.

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 two SBR40U45CT Schottky rectifiers connected in parallel, each one cabled of delivering up to 40 A (20 A per internal diode at 110º C, maximum voltage drop of 0.52 V). This gives us a maximum theoretical current of 57 A or 686 W for the +12 V output. These rectifiers are more powerful than the ones used on Silencer 610 EPS12V (two 30 A rectifiers).

The +5 V output is produced by one STPS60L30CW Schottky Rectifier, which is capable of delivering up to 60 A (30 A per internal diode at 130º C, 0.38 V typical voltage drop). This gives us a maximum theoretical current of 43 A or 214 W for the +5 V output. This rectifier is way more powerful than the one used on Silencer 610 EPS12V.

The +3.3 V output is produced by one STPS30L30CT Schottky rectifier, which is capable of delivering up to 30 A (15 A per internal diode at 140º C, 0.37 V typical voltage drop), giving us a maximum theoretical current of 21 A or 71 W for the +3.3 V output. This component is similar to the one used on Silencer 610 EPS12V from PC Power & Cooling.

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.

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Figure 14: +12 V, +5 V and +3.3 V rectifiers.

The outputs are monitored by an HY510N integrated circuit, which supports only over voltage (OVP) and under voltage (UVP) protections. Any other protection that this unit may have is implemented outside this integrated circuit.

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Figure 15: Monitoring integrated circuit.

Electrolytic capacitors from the secondary are also Japanese, from Chemi-Con and labeled at 105º C.

Power Distribution

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

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Figure 16: Power supply label.

This power supply is based on a single-rail design, so there is not much to talk about here.

Now let’s see if this power supply can really deliver 650 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 +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test both were connected to the single +12 V rail provided by this power supply (the +12VB input was connected to the EPS12V connector from the power supply, while the +12VA input was connected to the other cables).

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)	10 A (120 W)	15 A (180 W)	20 A (240 W)	24.5 A (294 W)
+12VB	5 A (60 W)	10 A (120 W)	15 A (180 W)	20 A (240 W)	24.5 A (294 W)
+5V	1 A (5 W)	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 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	141.5 W	271.5 W	411.3 W	550.2 W	660.0 W
% Max Load	21.8%	41.8%	63.3%	84.6%	101.5%
Room Temp.	45.9º C	45.3º C	46.0º C	47.6º C	48.5º C
PSU Temp.	50.5º C	50.5º C	50.9º C	52.3º C	54.3º C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	166.6 W	314.3 W	479.5 W	654.0 W	810.0 W
Efficiency	84.9%	86.4%	85.8%	84.1%	81.5%
AC Voltage	117.2 V	115.4 V	113.7 V	112.4 V	110.2 V
Power Factor	0.978	0.989	0.992	0.994	0.994
Final Result	Pass	Pass	Pass	Pass	Pass

XFX 650 W XXX Edition can really deliver its labeled wattage at high temperatures.

Efficiency was high when we pulled up to 80% from its labeled wattage (i.e., up to 520 W), being between 84.1% and 86.4%. At full load (650 W) efficiency dropped to 81.5%, still above the 80% mark.

Voltages were always inside the allowed range. The manufacturer promises a tight 3% regulation, which proved to be true. This is terrific: the voltages provided by this power supply are closer to their nominal values than required (ATX specification allows a 5% tolerance – 10% for the -12 V).

Noise and ripple levels were another highlight from this product, being always low. Below you can see these levels with the power supply delivering 660 W (test five). The maximum allowed is 120 mV for the +12 V output and 50 mV for the +5 V and +3.3 V outputs. All numbers are peak-to-peak figures.

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Figure 17: +12VA input from load tester at 660.0 W (37.4 mV).

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Figure 18: +12VB input from load tester at 660.0 W (47.4 mV).

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Figure 19: +5V rail with power supply delivering 660.0 W (21.6 mV).

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Figure 20: +3.3 V rail with power supply delivering 660.0 W (26.2 mV).

Now let’s see if we could pull more than 650 W from this unit.

Overload Tests

First we lowered current at +5 V and +3.3 V to 1 A each and maxed out the +12 V inputs from our load tester (33 A each). At 66 A the power supply didn’t shut down, meaning that either this unit doesn’t have over current protection (OCP) - which is more probable - or that it is configured at a value above that.

Then we tried to find the maximum values this unit could work with its outputs still inside specs, which came to 30 A on each +12 V input (i.e., 60 A total), with the power supply delivering around 745 W. The problem was that under this configuration the unit burned after one minute. Upon opening the unit and testing the main components, we discovered that one of the +12 V rectifiers was burned.

Main Specifications

XFX 650 W XXX Edition power supply specs include:

• ATX12V 2.3
• EPS12V 2.93
• Nominal labeled power: 650 W at 50º C.
• Measured maximum power: 660.0 W at 48.5º C.
• Labeled efficiency: 85% maximum at typical load (i.e., at 325 W) (80 Plus Bronze certified)
• Measured efficiency: Between 81.5% 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 20/24-pin connector, two ATX12V connectors that together form an EPS12V connector and one EPS12V connector (all permanently attached to the power supply).
• Video Card Power Connectors: One six-pin connector permanently attached to the power supply and three six/eight-pin connectors (one permanently attached to the power supply and two using the modular cabling system). All using individual cables.
• SATA Power Connectors: Six in two cables.
• Peripheral Power Connectors: Six in two cables.
• Floppy Disk Drive Power Connectors: Two in two cables.
• Protections: Over voltage (OVP, not tested), under voltage (UVP, not tested), over power (OPP, not tested) and short-circuit protection (SCP, tested and working).
• Warranty: Five years
• Real Manufacturer: Seasonic
• More Information: http://www.xfxforce.com
• Average price in the US*: USD 130.00 (USD 100 after a USD 30 mail-in rebate).

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

Conclusions

XFX 650 W XXX Edition is a very good power supply, being capable of delivering its labeled wattage at high temperatures, keeping high efficiency if you pull up to 80% of its labeled capacity (i.e., up to 520 W), a three percent voltage regulation (as opposed of 5% as defined on the ATX specification – translation: voltages closer to their nominal values than required), low noise and ripple levels, modular cabling system and a single-rail design.

Another nice feature is the presence of four connectors for video cards, allowing you to install two video cards that require two power connectors each. Some 650 W power supplies from other manufacturers have only two of them, and some users only discover this when it is too late (i.e., after buying a second video card and trying to install it).

It presents a good value for the average Joe, especially if you can get the USD 30 mail-in rebate being offered at Newegg.com, making this unit to cost only USD 100 (Newegg.com is also giving a discount of USD 55 or USD 60 if you buy this unit together with a Radeon HD 5870 or HD 5850 from XFX, respectively). And the five-year warranty certainly counts positive points towards this unit.

When we opened this power supply and saw that the printed circuit board was from PC Power & Cooling Silencer EPS12V series, we thought that this unit could be a relabeled Silencer 610 with a modular cabling system added, but our suspicion didn’t hold true: this 650 W unit uses rectifiers with greater current limits on the secondary, plus more powerful transistors on the active PFC circuit.