Corsair CX650 Power Supply Review

Capable for the mid-range

Corsair CX650 PSU
(Image: © Tom's Hardware)

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Protection Features

Check out our PSUs 101 article to learn more about PSU protection features.

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Protection Features

 

OCP

12V: 69A (127.78%), 11.908V 5V: 33.5A (134%), 4.976V 3.3V: 37.5A (150%), 3.275V 5VSB: 5.4A (180%), 4.914V

OPP

834.93W (128.45%)

OTP

✓ (95°C @ +12V heat sink)

SCP

12V: ✓ 5V: ✓ 3.3V: ✓ 5VSB: ✓ -12V: ✓

PWR_OK

Accurate but lower than 16ms

NLO

SIP

Surge: MOV Inrush: NTC Thermistor

OCP at 12V is appropriately set, but this is not the case for the minor rails where OCP is set sky-high. OPP's triggering point is within the 130% range, so everything is okay, while OTP's setting is low, since this PSU is rated at 40 degrees Celsius for continuous max load delivery. 

Leakage Current

In layman's terms, leakage current is the unwanted transfer of energy from one circuit to another. In power supplies, it is the current flowing from the primary side to the ground or the chassis, which in the majority of cases is connected to the ground.

The leakage current test is conducted at 110% of the DUT's rated voltage input (so for a 230-240V device, we should conduct the test with 253-264V input). The maximum acceptable limit of a leakage current is 3.5 mA.

(Image credit: Tom's Hardware)

Leakage current is at low levels. 

DC Power Sequencing

According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V outputs must be equal to or greater than the 3.3V rail at all times. Unfortunately, Intel doesn't mention why it is so important to always keep the 3.3V rail's voltage lower than the levels of the other two outputs.

Everything rolls fine here since 3.3V rail is always at a lower level than the other two. 

Cross Load Tests

To generate the following charts, we set our loaders to auto mode through custom-made software before trying more than 25,000 possible load combinations with the +12V, 5V, and 3.3V rails. The deviations in each of the charts below are calculated by taking the nominal values of the rails (12V, 5V, and 3.3V) as point zero. The ambient temperature during testing was between 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit).

Load Regulation Charts

Efficiency Chart

(Image credit: Tom's Hardware)

Ripple Charts

The lower the power supply's ripple, the more stable the system will be and less stress will also be applied to its components.

Infrared Images

We apply a half-load for 10 minutes with the PSU's top cover and cooling fan removed before taking photos with a modified FLIR E4 camera able to deliver an IR resolution of 320x240 (76,800 pixels).

The hottest spots are on the secondary side, in the PCB that hosts the DC-DC converters. There are some electrolytic caps close to these converters. Ideally, there should be more clearance between the caps mentioned above and the VRMs, and there is free space on the PCB for this, which GW didn't exploit, unfortunately. 

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • mdd1963
    Lots of folks 'poo-poo' some of Corsair's PSU offerings, instead flocking to something w/Gold or Platinum in it'/s title, no matter the 150% price increase, and/or the 430W 'only' capacity...

    I've been happily using a Corsair 600 watt PSU (CX600) which cost me all of $55 or so in Feb 2017 if I recall correctly... ; never a stutter.
    Reply
  • grmaster
    any specific reason why this platform is so bad at advance transient response at 12v
    Reply