Sometimes one sees an offer one just cannot refuse. I was in this situation last week when I saw a Corsair AX860 PSU on offer for $158.
I had bought a Corsair TX750M for $130 to put into my NAS (AMD A8 5600K) and my reason for doing so was to have a replacement PSU on hand if the one in my main machine ever gave up the ghost. I bought the AX860 to replace it and I sold the TX750M to my friend for the price I paid for it. He will be paying it up for the next few weeks and I installed it for him, so I was not taking advantage of him and the PSU itself is only a couple of months old.
It was interesting to discover in the handbook that the AX860 is rated as at least 2% more efficient here in the UK where we use 230Vac as opposed to the 110Vac used in the US.
I saw a number of complaints with regard to "coil whine" from the AX860. To preface this I have to say that cats, dogs and computers like me - humans not so much. This could be because of my autism and cats, dogs and computers have a zero BS tolerance, whereas I have found that people actually expect you to bullsh*t them. Anyway the first thing I did was to run Prime98 on the system after I had installed the PSU and ran that for 24 hours, I also had a number of videos running as well just to give the GPU something to do as well.
I had the PSU switch set to "hybrid" and after the 24 hours (it was a bit more than that) the fan was still stationary, and the PSU was barely warm. I have the PSU mounted at the bottom of the case so that the fan is facing upwards into the chassis and not facing down (although the housing I have, the CoolerMaster HAF XM, does have a filter on the bottom grill). I could not imagine installing the PSU with the fan facing downwards because I anticipated it would be running in fanless mode most of the time anyway but this way any heat generated will rise past the fan and it will be replaced by air entering through the back grill.
Now back the the topic of "coil whine". I didn't notice any, in fact the only thing I noticed was when I turned the regulator I have the fan on the Corsair H60 watercooler attached to up to maximum (which made all of four degrees Celsius difference) otherwise the computer was silent; and by silent I mean that I do not notice from the computer being less than a foot and a half away from my ear whether or not the computer is running or asleep. There are four 200mm fans, one 140 mm fan and a 120 mm fan running in the chassis.
When I say that I didn't notice any "coil whine" I mean that I had my ear pressed against the top of the PSU when the system was running and I had an earplug in my other ear and I heard absolutely NOTHING. As I stated above I have always had my hardware behaving nicely towards me (with very few exceptions, I have had one Tyan and one ASUS motherboard die on me; and my very first 1 GB drive, a Seagate, developed the click of death after a few months in 30 years).
With regard to PSUs though, since I moved to the UK from Germany I had, before I bought the Corsair AX850 for my main machine a total of six PSUs die in a ten year period. In Germany I had a total of one PSU die in about sixteen years and it had been running in various machines for about eight or nine years. A few months ago there was a power surge in the building I live in and two of my upstairs neighbours had their PSUs blow on them, one of the neighbours lost his motherboard as well. Luckily I had spares - even an old 775 motherboard which had been kicked around my place quite a lot and astoundingly still worked - so they had everything back up an running again. My AX850 stopped, but after I had disconnected the power lead for ten minutes when I reconnected it the whole system came back up none the worse for the experience.
CoolerMaster HAF X, i7-990x, Gigabyte X58A-UD3R, 24GB Corsair XMS, Sapphire 7950 Vapor-X, Corsair Neutron 128GB, 3*Seagate HD (3TB), Seagate HD (1.5TB), Hitachi HD (2TB), Plextor DVD + BluRay, StorageWorks DAT 72, 29160 SCSI Adapter, Corsair H80