I recently bought a new computer and chose the new 80 Plus Gold-certified HX750, mainly because the HX750 I bought last year (for another system) has performed very well. The new PSU seems to have a defective fan controller though.
The new PSU have sudden fan surges.
Irrespective of whether the system is in load or idle, the fan goes up to 100% speed for 2-3 seconds. Then the fan is immediately throttled down to a complete halt, which takes approx. 12-15 seconds. This happens over and over, with 7-9 minutes between the surges. When the fan controller is not malfunctioning it regulates the fan to run at relatively low, barely audible, speeds.
I have done the following troubleshooting to see if anything could be done about it:
1) Read: http://forum.corsair.com/forums/showthread.php?t=85166
2) Disabled fan control for other the other fans in my chassi, ran monitoring software and ocularly inspected that the sensor readings were correct.
3) Removed the PSU intake dust screen in my chassi to make sure it was not a matter of too little air coming through.
4) Checked and found that the PSU is lukewarm (as expected) to the touch.
5) Removed the graphics card from my system, running on Intel HD Graphics 4000, to minimize power draw/cooling needs.
These actions have not improved the situation at all, and the PSU which supposedly should support fanless (passive) operation up to 20% (150W) load, continues to run the fan at recurring intervals.
I do not believe that the fan controller have been so poorly designed as to operate like this, given that it seems able to run the fan relatively slowly when I run the system at full load. I need a confirmation that my PSU is not working as intended as soon as possible -- mainly because I still have an option to send it back and get a full refund from my reseller, if it indeed is designed to operate like that.
I want to keep it, but I can't endure the noise level it currently produces.
Please help me sort this out. Thanks in advance!