Cooler Master GX III 850w 80 PLUS Gold ATX 3.0 PSU Review

Introduction, Specifications, and Pricing

When we last built the Qube 500 from Cooler Master, we installed the GX III 850w ATX 3.0 PSU to review in the future. Well, that wait is over, and today is the day we talk about the GX III 850w ATX 3.0 PSU. Cooler Master boasts an innovative, streamlined design with ATX 3.0 support and a 90-degree 12VHPWR cable. Also, the GX III 850w is optimized for silent thermal performance and touted to hit Titanium level efficiency at light loads. The GX III 850w has fully modular cabling and a lengthy 10-year warranty.

So, with the intro out of the way, let's check out this new powerplant from Cooler Master.

Best Deals: Cooler Master GX III 850w 80 PLUS Gold ATX 3.0 PSU

	Today	7 days ago	30 days ago
	$380 USD	$380 USD	$339 USD	Buy
	$110.99 USD	$110.99 USD	$110.99 USD	Buy
	$380 USD	$380 USD	$339 USD	Buy
	$153.99 CAD	$153.99 CAD	$153.99 CAD	Buy
	£162.96	£162.96	£170.16	Buy
	$380 USD	$380 USD	$339 USD	Buy
* Prices last scanned on 3/17/2025 at 3:57 pm CDT - prices may not be accurate, click links above for the latest price. We may earn an affiliate commission from any sales.

Packaging

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Kicking things off with the packaging, Cooler Master is showing off their signature purple color with the GX III 850w PSU on the outside.

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Next up on the outside of the packaging is the specification for the GX III 850w Gold PSU. The fan curve and power efficiency graphs also show the relevant data.

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On the backside of the packaging, Cooler Master has shown other features of the GX III 850w PSU, notably the standby efficiency, the 90-degree 12VHPWR cable, fanless mode for the internal fan, an anodized heatsink, 100% Japanese capacitor, and lastly, a sleek screwless front panel design.

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Opening up the packaging shows the manual and warranty information. The cables are all in a clear plastic bag. There is no separate cable pouch here, peeps.

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Packaged and protected in dense black foam and a clear plastic bag, the GX III 850w ATX 3.0 PSU arrived pristine.

Outside the Cooler Master GX III 850w ATX 3.0 PSU

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The fan grill side of the Cooler Master GX III 850w ATX 3.0 PSU sports an innovative design that streamlines the overall aesthetic, which also greatly improves airflow. The grill has a honeycomb construction (but it looks very similar to the Cooler Master logo) to aid in unobstructed airflow. Inside are fortified brackets to aid in the overall construction strength.

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Now, Cooler Master wants you to know that nothing is wrong with the PSU if the fan does not spin up immediately. It must reach a specific core temperature; the fan will spin to cool down.

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The rear of the GX III 850w has a honeycomb pattern, just like the front grille. Very little to report here.

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Specwise, the GX III 850w has 70.8 amps on a single 12V rail with 850 watts available. The GX III 850w is also rated 80 Plus Gold, which means it is usually most efficient at a 50% load while maintaining 90% power efficiency. However, the GX III has a trick up its sleeve; it can reach 80 Plus Titanium levels of efficiency at lower loads.

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Along the side of the GX III 850w is the name and Cooler Master's purple logo.

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The top of the GX III 850w has this cool design of the full Cooler Master logo with purple and silver-like lightning bolts.

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The cable input side of the GX III 850w has the 12VHPWR input in the upper left corner, followed by five 8-pin PCIE/CPU hybrid inputs. The lower section has three 5-pin SATA/HDD inputs with two inputs for the motherboard, one 10-pin and another 18-pin.

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The cabling is all laid out, with all but the 12VHPWR cable in flat black ribbon. The 12VHPWR cable is sleeved, making it stand out among the rest of the cabling.

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The 12VHPWR cable is limited to 450 watts. The GPU end is at a 90-degree angle to help with the newer NVIDIA RTX GPUs while traditionally mounted to aid in less connector angle stress.

Inside theCooler Master GX III 850w ATX 3.0 PSU

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Popping off the GX III 850w grille is a shiny 135mm fan with an HDB bearing inside.

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Oddly enough, the 135mm fan is not a Cooler Master fan, which is disappointing. The fan is a Yate Loon, model D14SH-12, with an 11-blade design. It runs at 1900 RPM with .7 amps. The D14SH-12 was a decent fan back in the day, but it would have been nice to see a newer fan from Cooler Master in their newer PSU, maybe a Mobius 140.

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Here is an overall view of all the components of the Cooler Master GX III 850w ATX 3.0 PSU. The OEM is from Lite-On, a company we last heard from a while ago, which is traditionally known for making power adapters.

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The single large capacitor, which Cooler Master states is 100% Japanese, is from Toshin Kogyo. Model number LGWA 330428. They are rated for 450v at 680?F at up to 105C. Capacitors from TK are a good price-to-performance ratio balance, often found in mid-tier PSUs.

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The main transformer, tucked in the middle of the design, raises or lowers the voltages as needed.

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Another part labeled 37-PS58511L01.

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Cooler Master has also put their purple flare on the two internal heatsinks, both having an anodic coating that keeps average temperatures 5C lower than traditional heatsinks, which also helps enhance durability and a prolonged lifespan.

Test System, Installation, and Finished Product

• Motherboard: B650I AORUS Ultra(AMD B650) - Buy from Amazon
• CPU: AMD Ryzen 9 7900 - Buy from Amazon
• Cooler: AMD Wraith Prism - Buy from Amazon
• Memory: Corsair Dominator Platinum DDR5-7200 32GB - Buy from Amazon
• Graphics Card: Zotac RTX 3090 Trinity - Buy from Amazon
• Storage: Kingston Fury Renegade 1TB Gen4 PCIe x4 NVMe M.2 SSD - Buy from Amazon
• Case: Cooler Master Qube 500 Macaron Edition - Buy from Amazon
• Power Supply: Cooler Master GX III 850w ATX 3.0 PSU - Buy from Amazon
• Testing Software: AIDA64 Engineer 7.00.6700, HWiNFO64 v7.68-5300, TechPowerUp GPU-Z v2.57.0, and CPU-Z 2.0.9.0.x64.

Final Thoughts

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Testing the GX III 850w ATX 3.0 PSU from Cooler Master, the suite of mITX hardware was used. They consist of an AMD Ryzen 9 7900 12 core 24 thread CPU on the B650 AORUS Ultra AM5 motherboard. Cooling the Ryzen 9 7900 was the AMD Wraith Prism, which is rated for 105w TDP, which is plenty for this 65w TDP CPU. In the two DDR5 memory slots are two sticks of Corsair's Dominator Platinum RGB DDR5-7200MT/s. The GPU is the Zotac RTX 3090 Trinity, which has three fans to help move air. Storage was handled by the Hyper Fury Renegade 1TB M.2 PCIe 4.0 SSD.

The GX III 850w was dealt a 50% load, reading 425 watts via a KillaWatt P3. The Ryzen 9 7900 drew about 90 watts alone; the discrete GPU, the Zotac RTX 3090 Trinity, needed around 265 watts of juice at full load while power was limited at 76% via MSI Afterburner. Adding in the motherboard, along with the two sticks of DDR5 and PCIe M.2 SSD, averages about 30 watts of power. Totaling all the wattages up is a total of 385 watts, thus making the GX III 850w hit its 80 Plus Gold rating with 90.6% efficiency.

All testing was completed using Aida64 Engineer's System Stability Test version v7.00.6700 for about 24 hours; the ambient temperature was 19C. Other monitoring software used was HWiNFO64 v7.68-5300, TechPowerUp GPU-Z v2.57.0, CPU-Z 2.0.9.0.x64, and MSI Afterburner v4.6.4.16255.

The GX III 850w ATX 3.0 PSU from Cooler Master is a mixed bag. While performing to the 80 Plus Gold certification, what stood out was the higher average price point, fan noise, and overall mid-grade components used. The high price point of $170 is much too high compared to other 850-watt 80 Plus Gold rated ATX 3.0 PSUs currently on the market, which are currently on sale for around $120 after rebates.

Next, when fully loaded, the fan noise is quite audible, a common trait of the Yate Loon fan. Lastly, the components used in constructing the GX III 850w ATX 3.0 PSU tell the story of mid-grade parts trying to fetch a high-grade price point. Ultimately, Cooler Master needs to rethink its pricing position with the GX III 850w to be competitive with value-conscious builders.