Corsair RMx Series Fully Modular 850W Power Supply Review
Introduction and Features
Corsair has just expanded their RM Series of PC power supplies to include a third line, the RMx Series, in addition to the original RM and RMi Series. The new RMx power supplies will be available in 550W, 650W, 750W, 850W and 1000W models and are designed by Corsair and built by Channel Well Technologies (CWT). We will be taking a detailed look at the new RM850x 850W PSU in this review.
The RMx Series power supplies are equipped with fully modular cables and optimized for very quiet operation and high efficiency. RMx Series power supplies incorporate Zero RPM Fan Mode, which means the fan does not spin until the power supply is under a moderate to heavy load. The cooling fan is designed to deliver low noise and high static pressure. All of the RMx power supplies are 80 Plus Gold certified for high efficiency.
The Corsair RMx Series is built with high-quality components, including all Japanese made electrolytic capacitors, and Corsair guarantees these PSUs to deliver clean, stable, continuous power, even at ambient temperatures up to 50°C.
Corsair’s new RMx Series power supplies are nearly identical to the current RMi Series units except for these differences:
• Lower cost
• No Corsair Link interface
• 135mm fan vs. 140mm fan
• Additional 550W model
The following table provided by Corsair gives a good summary of the differences and similarities between the RM, RMx, and RMi Series power supplies.
(Courtesy of Corsair)
Corsair RM850x PSU Features summary:
• 850W continuous DC output (up to 50°C)
• 7-Year Warranty and Comprehensive Customer Support
• 80 PLUS Gold certified, at least 90% efficiency under 50% load
• Fully modular cables for easy installation
• Flat ribbon-style, low profile cables help optimize airflow
• Zero RPM Fan Mode for silent operation up to 40% load
• Quiet NR135L fan for long life and quiet operation
• High quality components including all Japanese electrolytic capacitors
• Active Power Factor correction (0.99) with Universal AC input
• Safety Protections : OCP, OVP, UVP, SCP, OTP, and OPP
• MSRP for the RM850x : $149.99 USD
PSU 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 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
• AC Ripple and Noise
• Differential Temperature
The Corsair RM850x 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 (+12V)
• (3) 218W Precision resistor load bank (+12V)
• Switchable precision resistor load bank (-12V and +5VSB)
• Agilent 34401A digital multimeter (Accuracy ±0.0035% vDC)
• 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)
The following cables/connectors were used to connect the RM850x to the PCPerspective power supply test equipment.
• (1) 20+4 pin ATX
• (2) 8-pin EPS/ATX12V
• (6) 6-pin PCI-E
• (2) SATA
• (2) Molex