Corsair's SF450 is an SFX PSU featuring amazing performance and very silent operation. It easily takes the top place in the 450W SFX category and its only downside looks to be the increased price, which is justified by the excellent build quality.

Introduction

Except for SilverStone, most companies don't seem to care much about the SFX form factor. This is changing though, as Corsair recently introduced its SFX-based SF series. There are currently only two models, hitting the 450 and 600W capacity points (we'd really like to see the company come out with something under 400W too). Both SF units are 80 PLUS Gold-certified and feature fully modular cabling to simplify installation. In addition, Corsair implements a semi-passive mode called Zero RPM, which deactivates the fan under light loads to enable silent operation. A larger 92mm fan is used to further suppress acoustic output. In comparison, most SFX power supplies employ 80mm fans that spin faster, creating more noise. Finally, Corsair is only using Japanese capacitors, assuring you get years of trouble-free use from the SF-series PSUs, which are also backed up by a seven-year warranty.

In this review, we're evaluating the lower-capacity SF450. Thanks to its couple of PCIe connectors, this PSU won't have a problem supporting a high-end graphics card, allowing you to build a capable gaming system inside a small chassis with minimal space for the power supply.

Corsair specifically calls out its larger fan's specially-shaped blades that move more air through the SF450 with less noise compared to conventional fans. Part of this could be a result of Corsair checking blade balance during its quality control phase, avoiding any problems that might result from vibration at high speeds.

Of course, noise isn't always generated by the fan. It can also come from capacitors and coils creating what we refer to as coil whine. Corsair's engineers paid extra attention to the components they used in the SF family, circumventing this issue.

Specifications

On the product's official page, Corsair states that this product is engineered to meet maximum power output at a 40 °C temperature rating. However, in the technical specifications section, it's rated at 50 °C for full load. We'll determine which is right with our tests at greater than 40 °C ambient.

Since the supply's feature set includes over-temperature protection, we have nothing to worry about in case the thermals inside go sky-high. The PSU should shut down automatically to cool itself off.

We'd like the option to disable the SF450's semi-passive mode, though we do appreciate a long seven-year warranty. We can't help but wonder however why these PSUs weren't include in the recent warranty upgrade that Corsair provided to the AXi, HXi, RM and RMx lines (from seven years to ten years).

Power Specifications

Rail 3.3V 5V 12V 5VSB -12V Max. Power Amps 15 20 37.5 2.5 0.3 Watts 100 450 12.5 3.6 Total Max. Power (W) 450

The 5V rail can deliver more amperage than the 3.3V rail, though this won't matter in a contemporary system drawing most of its current from the +12V rail. There is a single +12V rail and it can deliver the PSU's full power alone (typical for a PSU equipped with DC-DC converters for generating the minor rails). Finally, the 5VSB rail has the typical capacity for a modern, low/mid-wattage PSU.

Cables And Connectors

Modular Cables Description Cable Count Connector Count (Total) ATX connector 20+4 pin (310mm) 1 1 4+4 pin EPS12V (400mm) 1 1 6+2 pin PCIe (400mm) 2 2 SATA (100mm+115mm+115mm+115mm) 1 4 Four-pin Molex (100mm+115mm+115mm+115mm) 1 4

All cables are flat and stealth. On top of that, they're pretty short since, most likely, the SF450 will be installed in small cases. Nevertheless, we think the main ATX cable is too short; it should at least be 35cm long.

A big asset of this PSU is the fact that it is equipped with two PCIe connectors on dedicated cables. Given that 450W is more than enough to feed a flagship graphics card and potent CPU, just one PCIe connector would have crippled this unit's usability.

Of course, we couldn't expect this PSU to have two EPS connectors, and the number of peripheral connectors is satisfactory. On the other hand, it would be nice to get a couple more SATA connectors, bringing the total to six, and we wonder why Corsair didn't offer a Berg (FDD) adapter. Most enthusiasts probably wouldn't use it, but a bundled adapter could have come in useful. Finally, all connectors use standard 18-gauge wires, which are recommended by the ATX spec.

Power Distribution

Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.

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