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[nextpage title=”Introduction”]

So far, there are four models within Corsair’s new HX power supply series with the 80 Plus certification: 650 W, 750 W, 850 W, and 1,050 W. We’ve already reviewed the 850 W model, which received our “Golden Award.” Let’s see if the 650 W model is also a good buy.

The 850 W model is manufactured by CWT; however, the 650 W model is manufactured by Seasonic, based on the G-650 model from this manufacturer. Therefore, they use a completely different internal design.

Corsair HX650 GoldFigure 1: Corsair HX650 Gold power supply

Corsair HX650 GoldFigure 2: Corsair HX650 Gold power supply

The Corsair HX650 Gold is 6.3” (160 mm) deep. It uses a 140 mm ball-bearing fan on its bottom (Yate Loon D14BH-12).

Corsair HX650 GoldFigure 3: Fan

This power supply has a partial modular cabling system, with six connectors: two for video card connectors and four for peripheral and SATA connectors. This power supply comes with the following cables:

  • Main motherboard cable with a 20/24-pin connector, 23.6” (60 cm) long, permanently attached to the power supply
  • One cable with two ATX12V connectors that together form an EPS12V connector, 25.6” (65 cm) long
  • Two cables, each with one six/eight-pin connector for video cards, 23.6” (60 cm) long, modular cabling system
  • One cable with four SATA power connectors, 21.6” (55 cm) to the first connector, 3.9” (10 cm) between connectors, modular cabling system
  • One cable with four SATA power connectors, 16.1” (41 cm) to the first connector, 3.9” (10 cm) between connectors, modular cabling system
  • Two cables, each with four peripheral power connectors, 17.7” (45 cm) to the first connector, 3.9” (10 cm) between connectors, modular cabling system
  • Two adapters to convert peripheral power connectors into floppy disk drive power connectors

All cables use 18 AWG wires, which is the minimum recommended gauge.The number of connectors is, in theory, adequate for a 650 W power supply, however, competing products come with four video card power connectors instead of only two, allowing you to install up to two high-end video cards that require two auxiliary power connectors each.

Corsair HX650 GoldFigure 4: Cables

Let’s now take an in-depth look inside this power supply.

[nextpage title=”A Look Inside the Corsair HX650 Gold”]

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.          

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

 

Corsair HX650 GoldFigure 5: Top view

Corsair HX650 GoldFigure 6: Front quarter view

Corsair HX650 GoldFigure 7: Rear quarter view

Corsair HX650 GoldFigure 8: The printed circuit board

[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.

In the transient filtering stage, this power supply is flawless.

Corsair HX650 GoldFigure 9: Transient filtering stage (part 1)

Corsair HX650 GoldFigure 10: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the Corsair HX650 Gold.

[nextpage title=”Primary Analysis”]

On this page, we will take an in-depth look at the primary stage of the Corsair HX650 Gold. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.        

This power supply uses one GBU10JL rectifying bridge, which is attached to an individual heatsink. This bridge supports up to 10 A at 100° C. In theory, you would be able to pull up to 1,150 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 W without burning itself out (or 1,035 W at 90% efficiency). Of course, we are only talking about this particular component
. The real limit will depend on all the components combined in this power supply.

Corsair HX650 GoldFigure 11: Rectifying bridge

The active PFC circuit uses two SPP20N60C3 MOSFETs, each one supporting up to 20.7 A at 25° C or 13.1 A at 100° C in continuous mode (note the difference temperature makes), or 62.1 A at 25° C in pulse mode. These transistors present a 190 mΩ maximum resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

Corsair HX650 GoldFigure 12: Active PFC transistors and diode

The active PFC circuit is controlled by an ICE3PCS01 integrated circuit.

The output of the active PFC circuit is filtered by a 470 μF x 420 V Japanese electrolytic capacitor, from Hitachi, labeled at 105° C.

Corsair HX650 GoldFigure 13: Capacitor

In the switching section, two P18N50C MOSFETs are employed using a resonant configuration. Each transistor supports up to 18 A at 25° C or 11 A at 100° C in continuous mode or up to 72 A at 25° C in pulse mode, with a maximum RDS(on) of 270 mΩ. 

Corsair HX650 GoldFigure 14: The switching transistors

The switching transistors are controlled by an ICE2HS01G resonant controller.

Corsair HX650 GoldFigure 15: Resonant controller and active PFC controller

Let’s now take a look at the secondary of this power supply.

[nextpage title=”Secondary Analysis”]

As one would expect in a high-efficiency power supply, the Corsair HX650 Gold uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses four PSMN2R6-40Y MOSFETs, each one supporting up to 100 A at 100° C in continuous mode, or up to 651 A at 25° C in pulse mode, with a maximum RDS(on) of 5.3 mΩ. These transistors are located on the solder side of the printed circuit board, using the power supply case as their heatsink.

Corsair HX650 GoldFigure 16: The +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, located on a daughterboard soldered to the main printed circuit board. The converters are controlled by a single APW7159 integrated circuit and use seven IPD060N03L G MOSFETs. Four of them are used by the +5 V output, and three of them are used by the +3.3 V output. Each transistor supports up to 50 A at 100° C in continuous mode and up to 350 A at 25° C in pulse mode, with a maximum RDS(on) of 6 mΩ.

Corsair HX650 GoldFigure 17: The DC-DC converters

Corsair HX650 GoldFigure 18: The DC-DC converters

The outputs of the power supply are monitored by a PS223 integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections. There are four OCP channels, one for +3.3 V, one for +5 V, and two for +12 V. The manufacturer, however, decided to use only one of the +12 V channels available, resulting in this unit having a single +12 V rail.

Corsair HX650 GoldFigure 19: Monitoring circuit

This power supply uses a mix of solid and electrolytic capacitors in its secondary. The electrolytic capacitors are also Japanese, from Chemi-Con and Rubycon, and labeled at 105° C, as usual.

Corsair HX650 GoldFigure 20: Capacitors

[nextpage title=”The +5VSB Power Supply”]

The +5VSB (a.k.a. standby) power supply is independent of the main power supply, since it is on continuously.

The +5VSB power supply uses an ICE2QR47565 integrated circuit, which incorporates the PWM controller and the switching transistor into a single chip.

Corsair HX650 GoldFigure 21: The +5VSB integrated circuit with an integrated switching transistor

The rectification of the +5VSB output is performed by an SBR10U45D1 Schottky rectifier present on the solder side of t
he printed circuit board. This component supports up to 10 A (5 A per internal diode at 110° C, 0.57 V maximum voltage drop).

Corsair HX650 GoldFigure 22: The +5VSB rectifier

[nextpage title=”Power Distribution”]

In Figure 23, you can see the power supply label containing all the power specs.

Corsair HX650 GoldFigure 23: Power supply label

As you can see, this unit has a single +12 V rail configuration.

Let’s find out how much power this unit can deliver.

[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 the behavior of the reviewed unit 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 powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (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. In 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, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector.)

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA 5 A (60 W) 10 A (120 W) 14.5 A (174 W) 19 A (228 W) 23.5 A (282 W)
+12VB 5 A (60 W) 10 A (120 W) 14 A (168 W) 19 A (228 W) 23.5 A (282 W)
+5 V 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) 1.5 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 138.6 W 270.6 W 392.5 W 525.4 W 651.4 W
% Max Load 21.3% 41.6% 60.4% 80.8% 100.2%
Room Temp. 47.3° C 46.5° C 46.9° C 48.2° C 46.9° C
PSU Temp. 48.4° C 48.5° C 48.5° C 49.0° C 50.5° C
Voltage Regulation Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 159.5 W 302.6 W 438.9 W 594.5 W 750.0 W
Efficiency 86.9% 89.4% 89.4% 88.4% 86.9%
AC Voltage 117.1 V 115.9 V 114.7 V 113.1 V 111.0 V
Power Factor 0.992 0.996 0.998 0.998 0.998
Final Result Pass Pass Pass Pass Pass

The 80 Plus Gold certification promises efficiency of at least 87% under light (i.e., 20%) load, 90% under typical (i.e., 50%) load, and 87% under full (i.e., 100%) load. The Corsair HX650 Gold was able to match these numbers for light and full loads at high temperatures. We didn’t test this unit at 50% load, but from the numbers achieved at 40% and 60% load, we can easily assume it can provide 90% efficiency at half of its labeled wattage.

Let’s discuss voltage regulation on the next page.

[nextpage title=”Voltage Regulation Tests”]

The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values. We consider a power supply as “flawless” if it shows voltages within 3% of its nominal values. In the table below, you can see the power supply voltages during our tests and, in the following table, the deviation, in percentage, of their nominal values.

The Corsair HX650 Gold presented outstanding voltage regulation, with all positive outputs within 2% of their nominal values, as you can see below.

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA +12.20 V +12.16 V +12.14 V +12.10 V +12.08 V
+12VB +12.20 V +12.16 V +12.12 V +12.08 V +12.03 V
+5 V +5.08 V +5.06 V +5.05 V +5.03 V +5.01 V
+3.3 V +3.34 V +3.33 V +3.30 V +3.29 V +3.27 V
+5VSB +5.01 V +4.98 V +4.96 V +4.93 V +4.90 V
-12 V -11.30 V -11.49 V -11.70 V -11.97 V -12.25 V
Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA 1.67% 1.33% 1.17% 0.83% 0.67%
+12VB 1.67% 1.33% 1.00% 0.67% 0.25%
+5 V 1.60% 1.20% 1.00% 0.60% 0.20%
+3.3 V 1.21% 0.91% 0.00% -0.30% -0.91%
+5VSB 0.20% -0.40% -0.80% -1.40% -2.00%
-12 V 6.19% 4.44% 2.56% 0.25% -2.04%

Let’s discuss the ripple and noise levels on the next page.

[nextpage title=”Ripple and Noise Tests”]

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed  are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The Corsair HX650 Gold provided extremely low ripple and noise levels, as you can see below.

Test 5

Input Test 1 Test 2 Test 3 Test 4
+12VA 10.0 mV 13.6 mV 17.2 mV 24.2 mV 29.4 mV
+12VB 9.4 mV 12.8 mV 14.8 mV 20.8 mV 25.0 mV
+5 V 5.4 mV 6.8 mV 7.8 mV 10.4 mV 13.0 mV
+3.3 V 6.8 mV 7.2 mV 8.6 mV 9.2 mV 13.6 mV
+5VSB 8.2 mV 11.2 mV 14.2 mV 16.4 mV 19.8 mV
-12 V 9.6 mV 10.6 mV 16.2 mV 28.4 mV 31.8 mV

Below you can see the waveforms of the outputs during test five.

Corsair HX650 GoldFigure 24: +12VA input from load tester during test five at 651.4 W (29.4 mV)

Corsair HX650 GoldFigure 25: +12VB input from load tester during test five at 651.4 W (25.0 mV)

Corsair HX650 GoldFigure 26: +5V rail during test five at 651.4 W (13.0 mV)

Corsair HX650 GoldFigure 27: +3.3 V rail during test five at 651.4 W (13.6 mV)

Let’s see if we can pull more than 650 W from this unit.

[nextpage title=”Overload Tests”]

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit passed this test, since it shut down when we tried to pull more than what is listed below. During this test, noise and ripple levels were still extremely low and voltages were within 3% of their nominal values.

Input Overload Test
+12VA 29 A (348 W)
+12VB 29 A (348 W)
+5 V 10 A (50 W)
+3.3 V 10 A (33 W)
+5VSB 3 A (15 W)
-12 V 0.5 A (6 W)
Total 794.8 W
% Max Load 122.3%
Room Temp. 44.8° C
PSU Temp. 48.6° C
AC Power 938.0 W
Efficiency 84.7%
AC Voltage 110.1 V
Power Factor 0.998

[nextpage title=”Main Specifications”]

The main specifications for the Corsair HX650 Gold power supply include:

  • Standards: ATX12V 2.31 and EPS12V 2.92
  • Nominal labeled power: 650 W at 50° C
  • Measured maximum power: 794.8 W at 44.8° C
  • Labeled efficiency: 80 Plus Gold certification (87% at light/20% load, 90% at typical/50% load, and 87% at full/100% load)
  • Measured efficiency: Between 86.9% and 89.4% 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 and two ATX12V connectors that together form an EPS12V connector, permanently attached to the power supply
  • Video Card Power Connectors: Two six/eight-pin connectors on two cables, modular cabling system
  • SATA Power Connectors: Eight on two cables, modular cabling system
  • Peripheral Power Connectors: Eight on two cables, modular cabling system
  • Floppy Disk Drive Power Connectors: Two through adapters
  • Protections (as listed by the manufacturer): Over voltage (OVP), under voltage (UVP), over current (OCP), and short-circuit (SCP) protections
  • Are the above protections really available? Yes.
  • Warranty: Seven years
  • Real Model: Seasonic G-650
  • More Information: https://www.corsair.com
  • Average Price in the U.S.*: USD 120.00

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

[nextpage title=”Conclusions”]

The Corsair HX650 Gold is a great power supply, with efficiency above 87% at high temperatures, excellent voltage regulation for its positive voltages, and extremely low noise and ripple levels. It also comes with a terrific price tag for what it offers (USD 120). The only negative point we could find with this power supply is the presence of only two video card power connectors, while competing products come with four.

It is USD 5 cheaper than the model it is derived from, the Seasonic G-650, but if you can spend USD 10 more, the Seasonic X-Series KM3 650 W is a better option, as it has a fully modular cabling system, four video card power connectors, higher efficiency, and even better voltage regulation.