The AX860i and HX1000i have a USB connection to the motherboard USB 2.0 ports. There has been much confusion over what the LED means.
If there is no software installed the LED will show green which indicated the USB link is active.
If Corsair Link is installed then the LED will alternate between green and red to show there is a data link connected. If the LED is red continually it simply means there is a lot of data flowing.
Using a custom fan profile in Corsair Link will cause the software to poll the PSU to check conditions and set the fan speed accordingly.
The CPU on the PSU is comparatively basic. The USB port is intended to monitor the PSU power, change the OCP settings and even set a custom fan profile as desired.
The HX1000i shows red almost constantly which simply means the Corsair Link software is communicating with the PSU.
With a larger chassis, a Corsair water cooler can also be monitored so that a custom fan profile can be used or simply to monitor the pump. The popular H115i is a double fan 280mm cooler that is typically top mounted.
EVGA has made some video cards with a separate water cooler attached. The models seen have a single 120mm fan so it can replace the rear 120mm fan easily and it offers the benefit of additional chassis cooling. The video card itself has many sensors which gives this design some merit.
The AX860i had a problem shutting the machine down randomly. It’s not clear what the problem is but many users reported this fault. The LED on the AX860i turned red even though there was no software installed. This suggested a logic fault. Corsair sent the HX1000i as a replacement.
The AX860i sometimes would not even POST after a fault. Sometimes after a period of time it would allow the machine to reboot.
Using the Link software and a custom fan profile stabilized the AX860i. This is unusual behaviour which need clarification. With the custom fan the shutdown problem was eliminated.
ZERO FAN WOES
The Honeywell air purifier in the studio makes a lot of noise due the high air flow. The unit is an electrostatic design so materially improves air quality. The high setting is louder however it is not generally needed.
The zero fan may make the unit quiet but the heat does not do the hardware any favors. Here the desired for long service life outweighs the noise of a fan. A fan at low RPM is not very noticable. Inside a PC the fan noise is muffled by the panels.
Enabling the fan on the HX1000i reduced the temperature by 30°C which is stupendous. This can result in much more service life. The warranty is all fine and dandy but an RMA is very expensive both parties so the custom fan at low RPM is hard to notice and it does wonders for the cooling.