Asus ROG Strix 750W Power Supply Review

The Asus ROG Strix with 750W max power achieves high performance, and on top of that, it features dead silent operation (Cybenetics LAMBDA-A). Nevertheless, its price is stiff, with the competing offerings from Corsair (RM750x), Seasonic (Focus GX-750), and XPG (Core Reactor 750W), costing notably less. The main difference between the Rog Strix units and the similar capacity Seasonic models are the larger heat sinks, which allow for lower fan speeds, dropping the noise output significantly. But are you willing to pay a price difference of around 35 dollars for this?

The ROG Strix power supply line consists of only two models, with 650W and 750W max power. Seasonic makes both and, to be more specific, they utilize the Focus Plus Gold platform, which the Seasonic GX-650 and GX-750 models also use. This is a highly popular platform, offering a high performance per buck ratio. Asus asked Seasonic for some hardware changes to make its models as quiet as possible. The significant difference is depicted on the beefier heat sinks, which allow for a lower airflow, consequently less noise output from the fan. The second, major, difference is the double ball-bearing fan, which is more suitable for operating under high operating temperatures, compared to fluid dynamic bearing fans, 

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Product Photos

The ROG Strix 750 is fully modular and comes with two EPS and four PCIe connectors, so it will easily support a potent system. Besides an 80 PLUS Gold certification, it also bears efficiency and noise certifications by Cybenetics, ETA-A, and LAMBDA-A, respectively.

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Product Photos

Specifications

Power Specifications

Cables & Connectors

There is a large number of connectors, including two EPS, which is the trend nowadays for most mid-capacity power supplies. The length of the EPS cables is impressive, at one meter. ROG made sure that there won't be a compatibility issue with the EPS cables of this unit, even with large full tower chassis. 

The first SATA cable has enough distance between the connectors, while the second SATA cable has a smaller distance for drives installed nearby. Unfortunately, the 4-pin Molex connectors only have 120mm distance between them, while the ideal is 150mm. 

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Cable Photos

Component Analysis

We strongly encourage you to have a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss.

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Overall Photos

The PCB is a bit larger than the Seasonic GX-750 unit in order to accommodate the large APFC and primary heat sinks, which help in relaxing the fan speed profile. Moreover, the smaller heat sink that hosts the primary FETs has pretty large fins to dissipate heat faster. Besides the larger heat sinks and the different fan, there are no other notable differences with the similar capacity Focus Plus model. 

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Transient filter

The transient filter has two stages and has all the necessary parts, including four Y and two X caps, a discharge IC, two CM chokes, and an MOV. 

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Bridge rectifiers

The pair of bridge rectifiers can handle up to 30 Amps of current. 

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APFC converter

The APFC converter uses a pretty large bulk cap, which offers a longer than 17ms hold-up time. Right in front of the converter's FET and boost diode, we also find the NTC thermistor and relay combo, responsible for protection against large inrush currents. 

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Main FETs and primary transformer

The primary switching FETs are provided by Champion and are arranged in a full-bridge topology. Typically, an LLC resonant converter is used to boost efficiency. 

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12V FETs and VRMs

The +12V FETs are installed on the solder side of the PCB. The pair of heat sinks above them is used to cool them down. Two DC-DC converters are also used to generate the minor rails.  

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Filtering caps

The electrolytic filtering caps mostly belong to good Chemi-Con and Nichicon lines, with an increased lifetime. A large number of polymer caps are also used.

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5VSB Circuit

The standby PWM controller is an Excelliance MOS EM8569 IC. 

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Modular board front

Lots of polymer caps are installed at the face of the modular PCB. 

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Soldering quality

The soldering quality is very good, and on this side of the PCB, we also find several key components, including the APFC and resonant controllers, along with several diodes, the +12V FETs, and the supervisor IC. 

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Cooling fan

Contrary to its competitors, the ROG unit uses a double ball-bearing fan. This fan produces more noise, under the same operating conditions, compared to the sleeve, riffle, and fluid dynamic bearing ones, but they can handle increased temperatures without sweating. This is not a case for FDB fans whose life significantly degrades once the operating temperatures exceed 40 degrees Celsius. 

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