
The ASUS ROG LOKI SFX-L 850W is an 850W fully modular, SFX-L form factor, ATX 3.0 power supply with a single hybrid fan mode. As of publication date, it is priced at $220 USD MSRP. It is also available in white for $20 USD more directly from the ASUS e-store.
Performance tests indicate that this power supply delivers consistently good results, with a slight exception in the ripple tests, where values were higher but still within ATX specifications. Its load regulation and excursion performance are particularly strong, making it a recommended choice for those using high-power GPUs that require stable power delivery.
WHAT YOU NEED TO KNOW
THE GOOD
- Performance
It delivered stable load regulation and successfully sustained all power excursions, making it a reliable choice for demanding builds.
- Cables
The included cables are very flexible and have a braided-etched pattern, making it easy to cable manage.
THE BAD
- Nothing at the time of writing
THE REST
- Overall
The ROG LOKI SFX-L 850W is recommended due to its good load regulation and ability to handle power excursions effectively. Additionally, for users looking to enhance their aesthetic setup, the PSU supports Aura Sync and comes with an ARGB illuminated fan.
The ASUS ROG LOKI SFX-L 850W is an SFX-L form factor power supply, which is slightly longer than the standard SFX units by 30 mm, yet still compact enough for small form factor builds. The unit comes with a range of accessories, including Velcro cable ties and a cable bag. One of its standout features is the high-quality, flexible cables with a braided-etched pattern, which makes cable management easier.
For cooling, the unit is equipped with a 120mm dual ball bearing fan, which is larger than typical SFX fans, enhancing cooling performance. However, operating temperature is not specified by the manufacturer, and we were unable to verify this through testing.
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Front of the box.
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Power input side of the PSU.

Top of the PSU displaying the fan.

Bottom of the PSU displaying the specifications.
+12 V | +5 V | +3.3 V | +5 Vsb | -12 V | |
---|---|---|---|---|---|
CURRENT | 70.8 A | 20 A | 20 A | 2.5 A | 0.8 A |
WATTAGE | 850 W | 110 W | 12.5 W | 9.6 W | |
850 W |
Please note that the above ratings are manufacturer advertised specifications.
The ROG LOKI SFX-L 850W includes a hybrid fan mode, which ASUS markets as 0dB technology, ensuring the fan remains off when the PSU load is at or below 40%, reducing noise under low-load conditions. It comes with all of the standard protections expected from a high-end power supply and is backed by a 10-year warranty.
One notable feature is its support for Aura Sync, along with an ARGB illuminated fan that can be synchronized with other components in the system. ASUS includes a specific cable and Aura Sync connector to enable this functionality, providing users with aesthetic customization options.
In terms of performance, the ROG LOKI SFX-L 850W demonstrates good capabilities. During load regulation testing, there was only a 0.070V voltage drop on 12V rail across its full rated output power range of 850W, which is well within ATX specifications and better than other power supplies tested.
The power supply also met ATX ripple specifications, with a slightly high peak-to-peak ripple of 51 mV on the 12V rail. The 5V and 3.3V rails showed ripples of 44 mV and 46 mV, respectively. Usually output voltage ripple results are similar for 115V and 230V inputs, however, with this PSU they are rather different. Despite this, the ROG LOKI SFX-L 850W passed all power excursions, maintaining excellent voltage regulation in line with ATX standards.
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The ROG LOKI SFX-L 850W is 80PLUS Platinum certified, achieving 93% efficiency at 50% load, which is excellent for a power supply of this class. However, it narrowly missed hitting all the Platinum efficiency points at 50% load on a 230V input. Despite this, its low load efficiency at 230V input was slightly below average, although it improved significantly at 10% load, where it reached about 90% efficiency.
In brownout performance, the power supply sustained a 13 ms dropout at full load for both 115V and 230V inputs, which is average for this class of PSU. The OPP engaged at a maximum of 137% of the rated load, and the 12V rail alone was capable of delivering 96A or 136% of its rating. The OCP triggered at 135% to 150% on the primary rails, with other rails engaging around 200%, ensuring robust protection against overloading.
