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[nextpage title=”Introduction”]

The CX series, also known as the Builder series, is the most entry-level power supply series from Corsair, with 400 W, 430 W, 500 W and 600 W models. The 400 W model has been discontinued by the manufacturer, leaving the 430 W model as the most entry-level power supply offered by Corsair. Let’s see if the Corsair CX430 is a good buy.

It is important to understand that while the CX400W was manufactured by Seasonic, the 430 W, 500 W, and 600 W models are manufactured by CWT, therefore the 430 W model uses an internal design that is completely different from the 400 W model.

Corsair CX430 power supplyFigure 1: Corsair CX430 power supply

Corsair CX430 power supplyFigure 2: Corsair CX430 power supply

The Corsair CX430 is 5.5” (140 mm) deep, using a 120 mm sleeve bearing fan on its bottom (Yate Loon D12SH-12, 2,200 rpm, 88 cfm).

This unit features active PFC, of course, and doesn’t come with a modular cabling system. The cables are protected with nylon sleeves and the unit comes with the following cables and connectors:

  • Main motherboard cable with a 20/24-pin connector, 23.6” (60 cm) long
  • One cable with two ATX12V connectors that together form an EPS12V connector, 23.6” (60 cm) long
  • One cable with one six/eight-pin connector for video cards, 23.2” (59 cm) long
  • Two cables, each with two SATA power connectors, 16.5” (42 cm) to the first connector, 5.9” (15 cm) between connectors
  • One cable with three standard peripheral power connectors and one floppy disk drive power connector, 16.5” (42 cm) to the first connector, 5.9” (15 cm) between connectors

All wires are 18 AWG, which is the minimum required gauge.

The cable configuration is compatible with an entry-level 430 W product, with only one video card power connector and a reduced number of SATA and peripheral power connectors.

Corsair CX430 power supplyFigure 3: Cables

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

[nextpage title=”A Look Inside The Corsair CX430″]

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 CX430 power supplyFigure 4: Top view

Corsair CX430 power supplyFigure 5: Front quarter view

Corsair CX430 power supplyFigure 6: Rear quarter view

Corsair CX430 power supplyFigure 7: 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 this power supply, this stage is flawless. It has one X capacitor and two Y capacitors more than the minimum required.

Corsair CX430 power supplyFigure 8: Transient filtering stage (part 1)

Corsair CX430 power supplyFigure 9: Transient filtering stage (part 2)

In the next page we will have a more detailed discussion about the components used in the Corsair CX430.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of the Corsair CX430. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU806 rectifying bridge on its primary, which, unfortunately, isn’t attached to a heatsink. This component supports up to 8 A at 100° C (if a heatsink is used; the manufacturer doesn’t say how much current this bridge supports when not attached to a heatsink), so in theory, you would be able to pull up to 920 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 736 W without burning itself out. Of course, we are only talking about this component, and the real limit will depend on all the other components in this power supply.

Corsair CX430 power supplyFigure 10: Rectifying bridge

The active PFC circuit uses two STP14NK50ZFP MOSFET transistors, each one supporting up to 14 A at 25° C or up to 7.6 A at 100° C (not
e the difference temperature makes) in continuous mode, or up to 48 A in pulse mode at 25° C. This transistor presents a 380 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistor will waste less power and the power supply will have a higher efficiency.

Corsair CX430 power supplyFigure 11: Active PFC transistors and diode

The electrolytic capacitor that filters the output of the active PFC circuit is from Samxon and labeled at 85° C.

In the switching section, two AOTF10N60 power MOSFETs are used in the traditional two-transistor forward configuration. Each one supports up to 10 A at 25° C or up to 7.2 A at 100° C in continuous mode, or up to 36 A at 25° C in pulse mode, with an RDS(on) of 750 mΩ, which is very high.

Corsair CX430 power supplyFigure 12: Switching transistors

The primary is controlled by the omnipresent CM6800 active PFC/PWM combo.

Corsair CX430 power supplyFigure 13: Active PFC/PWM combo controller

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

[nextpage title=”Secondary Analysis”]

The Corsair CX430 has four Schottky rectifiers attached to its secondary heatsink.

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. As an exercise, we can assume a duty cycle of 30%.

The +12 V output uses two MBR3045CTP Schottky rectifiers (30 A, 15 A per internal diode at 125° C, 0.65 V maximum voltage drop). This gives us a maximum theoretical current of 43 A or 514 W for the +12 V output.

The +5 V output uses one MBR2545CTG Schottky rectifier (30 A, 15 A per internal diode at 160° C, 0.82 V maximum voltage drop), giving us a maximum theoretical current of 21 A or 107 W for the +5 V output.

The +3.3 V output uses another MBR2545CTG Schottky rectifier, giving us a maximum theoretical current of 21 A or 71 W for the +3.3 V output.

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.

Corsair CX430 power supplyFigure 14: +5 V and the two +12 V rectifiers (the +3.3 V rectifier is on the other side of the heatsink)

This power supply uses an ST9S429 monitoring integrated circuit, which apparently is a rebranded S3515. This chip supports over voltage (OVP), under voltage (UDP), and over current (OCP) protections. There are two +12 V OCP channels, but the manufacturer decided to use only of them, making this unit a single-rail model. 

Corsair CX430 power supplyFigure 15: Monitoring circuit

The electrolytic capacitors available in the secondary are from Teapo and Samxon and labeled at 105° C.

[nextpage title=”Power Distribution”]

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

Corsair CX430 power supplyFigure 16: Power supply label

This power supply has a single +12 V rail, so there is not much to talk about here.

Let’s now see if this power supply can really deliver 430 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 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 both were connected to the power supply single +12 V rail (the EPS12V connector was installed on the +12VB input).


Input Test 1 Test 2 Test 3 Test 4 Test 5
+12VA 3 A (36 W) 6 A (72 W) 9 A (108 W) 12 A (144 W) 15.5 A (186 W)
+12VB 3 A (36 W) 6 A (72 W) 9 A (108 W) 12 A (144 W) 15.25 A (183 W)
+5V 1 A (5 W) 2 A (10 W) 4 A (20 W) 5 A (25 W) 7 A (35 W)
+3.3 V 1 A (3.3 W) 2 A (6.6 W) 4 A (13.2 W) 5 A (16.5 W) 7 A (23.1 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 90.6 W 170.2 W 257.9 W 338.7 W 431.9 W
% Max Load 21.1% 39.6% 60.0% 78.8% 100.4%
Room Temp. 45.5° C 44.0° C 44.3° C 47.9° C 49.6° C
PSU Temp. 45.7° C 45.8° C 46.1° C 48.0° C 49.8° C
Voltage Stability Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass
AC Power 110.1 W 202.3 W 310.6 W 415.6 W 543.8 W
Efficiency 82.3% 84.1% 83.0% 81.5% 79.4%
AC Voltage 118.4 V 117.6 V 116.4 V 115.5 V 115.2 V
Power Factor 0.922 0.928 0.943 0.952 0.957
Final Result Pass Pass Pass Pass Pass

The Corsair CX430 can really deliver its labeled wattage at high temperatures.

Efficiency was between 79.4% and 84.1%, which is compatible with a good entry-level product. In fact, since this unit doesn’t even have the standard 80 Plus certification, we were expecting it to present lower efficiency than it actually did.

Voltage regulation was superb, with all voltages within 3% of their nominal values, including the -12 V output. This means that voltages were closer to their nominal values than required by the ATX12V specification, which says positive voltages must be within 5% of their nominal values and negative voltages must be within 10% of their nominal values. This tighter regulation is great to be seen on a low-end power supply.

Noise and ripple levels were always extremely low. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 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.

Corsair CX430 power supplyFigure 17: +12VA input from load tester during test five at 431.9 W (28.2 mV)

Corsair CX430 power supplyFigure 18: +12VB input from load tester during test five at 431.9 W (27.2 mV)

Corsair CX430 power supplyFigure 19: +5V rail during test five at 431.9 W (10.2 mV)

Corsair CX430 power supplyFigure 20: +3.3 V rail during test five at 431.9 W (19.6 mV)

Let’s see if we can pull more than 430 W from this unit.

[nextpage title=”Overload Tests”]

Below you can see the maximum we could pull from this power supply. If we tried to pull more than that the unit shut down, showing that its protections were working well. It is important to know that during this test noise levels were way above the maximum allowed (e.g., 600 mV at +12V, 255 mV at +5 V, and 520 mV at -12 V), showing that the unit had already reached its limits.

Input Overload Test
+12VA 20 A (240 W)
+12VB 20 A (240 W)
+5V 10 A (50 W)
+3.3 V 10 A (33 W)
+5VSB 2 A (10 W)
-12 V 0.5 A (6 W)
Total 548.8 W
% Max Load 127.6%
Room Temp. 45.8° C
PSU Temp. 48.3° C
AC Power 737 W
Efficiency 74.5%
AC Voltage 112.6 V
Power Factor 0.965

[nextpage title=”Main Specifications”]

The specs of the Corsair CX430 include:

  • Standards: ATX12V 2.3
  • Nominal labeled power: 430 W at 30° C
  • Measured maximum power: 548.8 W at 45.8° C ambient
  • Labeled efficiency: Up to 80%
  • Measured efficiency: Between 79.4% and 84.1% at 115 V (nominal, see complete results for actual voltage)
  • Active PFC: Yes
  • Modular Cabling System: No
  • Motherboard Power Connectors: One 20/24-pin connector and two ATX12 V connectors that together form an EPS12V connector
  • Video Card Power Connectors: One six-pin
  • SATA Power Connectors: Four on two cables
  • Peripheral Power Connectors: Three on one cable
  • Floppy Disk Drive Power Connectors: One
  • Protections (as listed by the manufacturer): Over voltage (OVP), under voltage (UVP), over power (OPP), short-circuit (SCP)
  • Are the above protections really available? Yes. Over current protection (OCP) is present.
  • Warranty: Two years
  • Real Manufacturer: CWT
  • More Information: https://www.corsair.com
  • Average price in the US*: USD 45 (USD 25 after a mail-in rebate card)

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

[nextpage title=”Conclusions”]

The Corsair CX430 surprised us a lot. Because it doesn’t have even the standard 80 Plus certification, the manufacturer says it has efficiency “up to” 80%, and Corsair was apprehensive in sending us a reviewing sample (we had to buy this unit ourselves), we were expecting to see a unit with lousy efficiency. However, the CX430 proved to be a terrific entry-level power supply.

It can deliver its labeled wattage at high temperatures, it has a superb voltage regulation (3% regulation instead of the standard 5%, meaning that voltages are closer to their nominal values than necessary), ultra-low noise and ripple levels, and decent efficiency up to 84%. The cable configuration is compatible with an entry-level 430 W unit, and users that need more cables will have to buy a different product.

The only reason we are giving our “Silver Award” instead of “Golden” is the efficiency a tiny bit below 80% when the unit is delivering its 430 W, but it is, still, a highly recommended unit for entry-level systems, especially when you put price into equation: this unit costs only USD 45 bucks and if you hurry you can get a USD 20 mail-in rebate card at Newegg.com, making it to actually cost only USD 25 (yes, INSANE). But pay attention because you have to download a PDF with the instructions on how to get this card when checking out, most people forget to click on the link, get the instructions, and send in the required paperwork.