Introduction

Corsair has revamped the CX-M line, and the differences between the old and new one are immediately noticable from the exterior, thanks to a new design with triangular-shaped perforations on the fan and exhaust grilles. I have already evaluated the CX650M, so it's time to look at the smallest member of the CX-M line, with 450 W full power. The CX450M also uses a semi-modular cable design, with only the necessary cables fixed to its PCB. The efficiency certifications are Bronze in 80 PLUS, and Cybenetics and noise output is Cybernetics Standard++, meaning 30 to 35 dBA average noise output. Therefore the unit isn't among the quietest 450 W PSUs, the average efficiency sets limits on the fan speed profile, but the five-year warranty somewhat makes up for this. It is better to be on the safe side and not allow for increased internal temperatures, rather than provide low noise output even under harsh conditions, jeopardizing the PSU's health. If you need a silent PSU, you should shop for a highly efficient one, which costs more.

The CX450M is currently listed on Amazon at 50 dollars, with zero availability. On Newegg, its price tag is higher, and the same applies to the MSRP. The current shortages in parts and products seems to have affected the price. In Europe, there is availability, though, at less than 50 euros. In my country's most popular price search engine, I found the CX450M available at 44.32€ including free shipping! For users needing a budget PSU for a low-end PC, the CX450M is ideal at this price.

Specifications

Photos

On the face of the small box is a photo of the PSU with its fan grille and triangular-shaped perforations, making it easy to identify the new model from the old one.


Protection inside the box only consists of bubble wrap. It would be nice to see some packing foam.


The bundle includes the modular cables and AC power cord, a set of fixing bolts, and a leaflet containing "important" information.


The exhaust grille also has triangular perforations instead of the usual honeycomb-style ones.


Stickers with the model number are on the sides. The power specification label is on the bottom.


The modular board only has three sockets, while the CX650M has five. The fixed cables are fully sleeved, and a plastic grommet is on the cable-exit hole.


This is a compact-footprint PSU, measuring 140 mm in length.


Here are some more photos of the PSU from various angles.

Cables and Connectors

There are only two fixed cables, both are sufficiently long.


The single PCIe cable is modular and has two connectors. Two PCIe, even onto a single cable, are enough for a 450 W PSU. The number of peripheral connectors is also sufficient, but I would like to see a longer distance between them, 150 mm at least.

Component Analysis

Before reading this page, we strongly suggest looking at this article, which will help you better understand the insides of a PSU.



This is the same platform I found on the CX650M. It is CWT's CSB-A design, using a combination of old and new elements. On the primary side is a double-forward topology, which is considered outdated. In contrast, the secondary side has been given a modern touch with DC-DC converters to generate the minor rails. Corsair used good caps for this price range and a rifle-bearing fan to ensure that the PSU will easily outlive the five-year warranty.


The transient filter is complete.


There is an MOV for protection against power surges. An NTC thermistor handles inrush currents. The latter has no bypass relay, usually installed in more expensive platforms.


Finding a discharge IC in a budget PSU is nice.


The single bridge rectifier can handle up to 8 A, while in the CX650M, I found a 15 A bridge rectifier.


The APFC converter uses two Silan FETs and a single boost diode. The bulk cap is by Chemi-Con. Its capacity is not high enough to reach a 17 ms hold-up time.


The primary switching FETs are installed into a double-forward topology, which is outdated, but more affordable to implement.


The combo APFC and PWM controller is a Champion CM6800TX IC—a blast from the past. A Champion CM03X supports it for the low vampire power needs of today.


The unit's main transformer provides electrical isolation between the primary and secondary sides.


A mix of FETs and SBRs regulate the +12 V rail.


Most filtering caps are by Elite, the best alternative brand to Japanese caps, along with Teapo's products. Besides electrolytic caps, nine polymer ones are also used.


Two DC-DC converters generate the minor rails.


The standby PWM controller is a Power Integrations TNY290PG IC.


The supervisor controller is an INI1S429I - DCG.


The modular PCB has space for three more connectors, installed on higher-capacity CX-M models.


Soldering quality is decent.


The cooling fan is by Hong Hua and uses a rifle bearing.

Test Setup