Even though the efficiency of the
Corsair HX850 is undoubtedly great, it actually barely meets the certification
of an 80Plus Gold certified unit. The 80Plus Gold certification dictates that the
efficiency should reach 92% at 50% load when the unit is powered by a 230V A/C
power source, which the HX850 managed to just barely touch. Nonetheless, barely
or not, the HX850 does honor its 80Plus Gold certification.
When it comes to acoustics, the
HX850 displayed a rather peculiar behavior; the unit will remain virtually
silent up to 55-60% load, above which point the fan will start spinning notably
faster, essentially tripling the unit’s noise output within a very short range.
However, even when the HX850 is fully loaded, the noise level is just a bit
higher than 34dB(A), a noise level which is clearly audible but not annoyingly
loud, even for everyday use.
Despite the peculiar cooling fan
operational scenario, the thermal performance of the HX850 is pretty standard
and the PSU delivered excellent figures, even for an 80Plus Gold certified
product. The temperature delta between the ambient and the exhaust temperature
of the unit starts at about 4.2°C at 20% load and gradually increases, reaching
up to just shy of 10°C under maximum load.