Corsair Professional HX850 850W Power Supply Review

Testing Methodology

Sub-700W PSU test system has not yet been determined.

Test System Setup

Processor: Intel Core i7 920(ES) @ 4.0Ghz
Memory: Corsair 3x2GB Dominator DDR3 1600Mhz
Motherboard: Gigabyte EX58-UD5
Graphics Card(s): HD4870X2 Single and Crossfire (@stock speeds)
Cooling: CoolIT Boreas mTEC + Scythe Fan Controller
Disk Drive: Pioneer DVD Writer
Hard Drive: Western Digital Caviar Black 640GB
Additional Fans: 2x Yate Loon 1200RPM
Monitor: Samsung 305T 30” widescreen LCD
OS: Windows Vista Ultimate x64 SP1
* Open test bench


General Notes

*Each test is run over the course of 30 minutes.

*Please note that the Crossfire setup is only used for 900W and higher PSUs

*Unless otherwise noted, the Boreas TEC runs at a constant 100%


Idle Conditions

Off: Is a load value where the system is turned off but a small amount of power is still required.

Idle: Idle values are determined by a stable Windows Vista x64 desktop.

Idle + TEC: Reflects an idle conditions mentioned above but with the Boreas TEC’s running at 100% load

Idle + CF: Same idle conditions as indicated above with a pair of HD 4870X2 cards installed.


Load Conditions

CPU Load: This test is run with 8 instances of a custom Prime95 test which we have found uses the most non-GPU power. The test is run for 30 minutes.

GPU Load: For this test we are aiming to show power consumption in a typical fast-paced gaming scenario. As such, we load a single HD4870X2 with custom timedemo of Far Cry 2 at 2560 x 1600 with 4x AA enabled and set it to loop for approximately 30 minutes.

Max Load: For this test we use the single GPU setup running 3DMark06 Batch Render Test at 2560x1600 4xAA / 16xAF while running our custom Prime95 test on the CPU in the background. Once again, this is a 30 minute test.

Extreme Load Test: This is the big one which separates the boys from the men. Basically, it is the same test as the Max Load test but we add another HD4870X2 into the mix and tested for 30 minutes.


Voltage Regulation Testing Methodology

Multimeters Used:
Extech 430 DMM x3

*Note: All voltage readings indicated in the review are the minimum voltages seen over the period of our tests

We always take voltage readings from a loaded connector in order to more accurately see the voltage fluctuations our components are experiencing. Thus, this is how voltages are measured:

+12V: In the CPU Load test the voltages are taken directly from the CPU connector and the used 8-pin PCI-E connector of the power supply. In the GPU Load test the voltages are taken from an 8-pin PCI-E connector which is plugged in to the topmost graphics card as well as the CPU connector. In the Extreme Load test, readings are taken from both the CPU and the PCI-E connectors and the lowest reading is recorded.

+3.3V / +5V: From the main ATX connector.

Please note: Due to the lack of load on the +3.3V and +5V rails in a modern PC, we WILL NOT be including charts for their results unless there are noteworthy fluctuations.


AC Ripple Testing Methodology

Tolerances:

+12V : 120mV Max
+3.3V: 50mV Max
+5V: 50mV Max

The values were the highest peak ripple measurement across all of the +12V rails. So, if the +12V1 rail shows a ripple of 20mV and the +12V2 rail shows a ripple of 40mV, the highest value will be graphed.

Instruments Used:
USB Instruments Stingray Digital Oscilloscope
USB Instruments Differential Oscilloscope Probe

Since we do not have a load tester with a BNC connector for the standard o-scope probe, we needed a Differential probe in order to give us the proper capacitance to accurately determine ripple. In addition, the differential probe has a pair of connectors which are very much akin to a multimeter's probes which makes them ideal for use on SMPS designs. The locations of the probes for each test reflect the locations of the multimeter probes detailed in the Voltage Regulation Testing Methodology section.


Efficiency Testing Methodology


Instruments Used:
UPM Power Meter
Tripp Lite LC1800 Line Conditioner

The data points you see in our charts show the AVERAGE PEAK AC power consumption over all of the tests conducted.


Temperature Testing

Considering the amount of heat our open-air test system produces, it was found to be nigh-on impossible to properly regulate the temperature in the room even with a 10,000 BTU air conditioner. As such, we will be measuring the delta between room temperature and the exhaust temperature from the power supply.

To test temperature, we set up a pair of Type-K temperature probes. One is placed in the middle of the testing room at an elevation of 5 feet AFF to measure ambient temperatures. Meanwhile, the other temperature probe is placed 4” away from the exhaust grille of the power supply.


A few other tidbits

- AC Input Voltage: 120V constant
- Noise is subjectively tested