Corsair RM850x (2018) PSU Review

1. Introduction2. Packaging, Contents & Exterior3. Teardown & Component Analysis4. Load Regulation, Hold-Up Time & Inrush Current5. Efficiency, Temperature & Noise6. Protection Features & DC Power Sequencing7. Cross-Load Tests & Infrared Images8. Transient Response Tests9. Ripple Measurements10. EMC Pre-Compliance Testing11. Performance, Value, Noise & Efficiency12. Final Analysis13. View All Pages

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units.

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

Hold-Up Time

Our hold-up time tests are described in detail here.

The oscilloscope screenshots that we took during the hold-up time measurements:

The hold-up time is longer than 17ms and the power-ok signal is accurate and right on spot, at 16ms.

Inrush Current

For details on our inrush current testing, please click here.

The inrush current is quite high with both voltage inputs, especially with 230V.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the RM850x’s efficiency. The applied load equals (approximately) 10 to 110 percent of the power supplies maximum load in increments of 10 percentage points.

We conducted two additional tests.

During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a power supply is compatible with Intel’s C6/C7 sleep states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

Test #	12V	5V	3.3V	5VSB	DC/AC (Watts)	Efficiency	Fan Speed (RPM)	PSU Noise (dB[A])	Temps (In/Out)	PF/AC Volts
1	5.225A	1.980A	1.985A	0.994A	84.913	86.974%	0	<6.0	47.19°C	0.970
	12.115V	5.054V	3.326V	5.032V	97.630				40.12°C	115.05V
2	11.434A	2.970A	2.977A	1.194A	169.435	90.199%	0	<6.0	48.54°C	0.985
	12.116V	5.052V	3.323V	5.028V	187.846				40.99°C	115.05V
3	18.046A	3.466A	3.464A	1.394A	254.532	91.416%	0	<6.0	49.23°C	0.991
	12.109V	5.051V	3.321V	5.023V	278.433				41.17°C	115.05V
4	24.673A	3.962A	3.978A	1.595A	339.754	91.411%	0	<6.0	50.97°C	0.988
	12.100V	5.050V	3.318V	5.017V	371.676				41.78°C	115.05V
5	30.991A	4.955A	4.977A	1.796A	425.070	90.984%	610	10.2	41.98°C	0.989
	12.086V	5.047V	3.316V	5.012V	467.194				51.88°C	115.05V
6	37.258A	5.948A	5.977A	1.998A	509.599	90.471%	610	10.2	42.61°C	0.990
	12.072V	5.046V	3.313V	5.007V	563.272				53.01°C	115.05V
7	43.589A	6.942A	6.978A	2.200A	594.887	89.808%	610	10.2	43.30°C	0.991
	12.062V	5.044V	3.310V	5.002V	662.398				54.30°C	115.05V
8	49.928A	7.935A	7.982A	2.402A	680.257	88.988%	888	22.2	43.90°C	0.993
	12.054V	5.043V	3.308V	4.998V	764.437				55.60°C	115.04V
9	56.673A	8.434A	8.472A	2.402A	765.203	88.194%	1130	30.3	44.46°C	0.994
	12.046V	5.041V	3.305V	4.998V	867.641				56.50°C	115.04V
10	63.158A	8.931A	8.994A	3.013A	850.023	87.226%	1415	36.7	46.20°C	0.995
	12.038V	5.040V	3.303V	4.981V	974.511				58.61°C	115.04V
11	70.244A	8.935A	8.998A	3.014A	934.759	86.187%	1440	37.1	46.71°C	0.996
	12.030V	5.038V	3.301V	4.979V	1084.566				59.59°C	115.03V
CL1	0.146A	18.004A	17.999A	0.000A	152.460	81.936%	714	16.5	41.96°C	0.985
	12.097V	5.053V	3.318V	5.102V	186.071				51.73°C	115.06V
CL2	70.846A	1.000A	1.000A	1.000A	866.348	87.734%	1300	34.5	46.78°C	0.995
	12.040V	5.041V	3.306V	5.015V	987.473				58.74°C	115.04V

The load regulation is tight on all rails and the fan profile is super relaxed even under extremely stressful conditions. Moreover, the semi-passive operation lasts for quite long and doesn't seem to be affected by high operating temperatures. Although there are no heatsinks in the secondary side, CWT's platform doesn't seem to have any problem at all under increased temperatures.

The 80 PLUS Gold requirements with 20%, 50% and full load are easily met even with the tough conditions that we apply. This is something that we don't see everyday.

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