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Corsair HX850 Professional Series Power Supply Review

Manufacturer: Corsair

Introduction and Features

Corsair continues to bring a full line of high quality power supplies, memory components, cases, cooling components, SSDs and accessories to market for the PC enthusiast and professional alike.  Corsair's updated Professional Series HX power supplies include four models; the HX650, HX750, HX850 and HX1050.  All of the power supplies in the Professional Series feature modular cables, premium quality components, an energy-efficient design (now 80 Plus Gold certified) and quiet operation; and they are backed by a 7-year warranty and lifetime access to Corsair's comprehensive technical support and customer service. The most obvious differences between the new models and the old Professional Series HX PSUs are the new 80 Plus Gold efficiency certification (upgraded from 80 Plus Silver) and the ability to operate in fanless-mode.

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Here is what Corsair has to say about their new Professional Series HX PSUs:

"Legendary Performance and Reliability

Corsair Professional Series HX power supplies are designed for PC builders and upgraders who need a highly efficient, quiet, and supremely-reliable power supply, with a modular cable-set that makes installation a breeze.

Quiet Operation at Low Loads

Thanks to their highly-efficient design, Corsair Professional Series power supplies generate minimal heat, and are able to operate in a silent, fully-fanless mode at up to 20% of the PSU’s maximum load (170W for the HX850). This means that Professional Series HX PSUs will be completely silent when you’re performing less intensive tasks, such as web browsing or chatting in forums. And the thermally-controlled fan spins up gradually above 20% load, so that it still operates quietly during normal use and when gaming. Basic PC power supplies have fans that spin all the time your PC is on – whether you’re pushing your graphics card to the limit or just surfing the web – making them noisier and more intrusive.

Modular Cables for Easy Installation

Professional Series power supplies have a comprehensive modular cable set that allows you to use only the cables you need for your particular set of components. The benefits of this include a cleaner, neater installation, and that ‘professionally-built’ look, plus increased airflow through the case due to reduced cable clutter. The cables are also long enough to support full-tower cases.

80 PLUS Gold: High Efficiency – Low Heat

Efficiency is the measurement of how effectively a power supply converts AC power from your wall outlet to the DC power used by your PC’s components. If your power supply isn’t efficient, it will generate more heat, which requires more cooling and more fan noise. And, it might even affect your power bill.

Professional Series HX PSUs are among the most efficient on the market. Each model has 80 Plus Gold certification, which ensures up to 90% energy-efficiency. This helps to keep your PC cool and quiet, and it may even save you money too.


Professional Series HX PSUs are built with premium components, such as 105°C capacitors, and are capable of continuous power delivery at a temperature rating of 50°C, ensuring maximum performance and reliability even in the most demanding and hot-running performance PCs.

The Corsair Advantage

Corsair Professional Series PSUs are backed by a reassuring 7-year warranty and comprehensive customer support via telephone, email, forum and the Tech Support Express helpdesk."

Please continue reading our review of the Corsair Professional Series HX850!

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Corsair Professional Series HX850 PSU Key Features:

• 850W continuous power output (50°C)
• 80 PLUS Gold certified (up to 90% efficient under real-world loads)
• Single +12V rail offers simple configuration and maximum compatibility
• Silent, Fanless operation below 20% load
• Ultra-quiet 140mm double ball-bearing fan offers excellent airflow
• Advanced DC-to-DC converter circuitry
• Comprehensive hybrid modular cable system
• Universal AC input (90~264V) with Active PFC (0.99)
• Over-current, over-voltage, over power, under-voltage and short circuit protection
• High quality capacitors provide uncompromised performance and reliability
• Low profile, flat cable design reduces air friction and helps maximize airflow
• Conforms to ATX12V v2.31 and EPS 2.92 standards
• Backwards compatible with ATX12V 2.2 and ATX12V 2.01 standards
• 7-Year warranty and lifetime access to legendary Corsair customer service
• Safety Approvals: cTUVus, CE, CB, FCC Class B, TUV, CCC, C-tick

Testing Methodology

Establishing an accurate load is critical to testing and evaluating a PC power supply.  PCPerspective’s power supply test bench can place a precise 2,000 watt DC load on the PSU under test.  Each power supply is tested under controlled, real-world conditions up to its maximum rated load (at 40ºC), using both 115 VAC and 240 VAC line voltage.  Our current suite of tests includes:

• DC Load Regulation
• DC Line Regulation
• DC Cross-load (unbalanced load)
• AC Ripple and Noise
• Power Factor
• Efficiency
• Differential Temperature
• Noise

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The Corsair Professional Series HX850 power supply was evaluated on both features and performance.  A full range of equipment was used to test the power supply under controlled load conditions. 

• (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
• (4) CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• (2) 200W Precision resistor load bank (+12V5 and +12V6)
• Switchable precision resistor load bank (-12V and +5VSB)
• Extech MultiMaster MM570 digital multimeter (Accuracy ±0.02%)
• Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
• DS1M12 "StingRay" digital oscilloscope (20M S/s with 12 Bit ADC)
• Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC
• Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)