Don't forget, some users think that Corsair AX1200 (not "i") is silent, but look here:
I had it, but only for 15 mins
Unfortunately I bought it before I saw it. More than 1200 rpm at low loads
And again AX1200i:Same funs
, different control algorithm.
Now X-1250 Gold:
Maybe it was a bad device?
Cause it must be near to AX850:
And a quote from jonnyguru.com
(the pictures above not from his site):
"Now, about the semi-fanless mode. Where did I see the fan start? In test one. The unit would only run the low load test in fanless mode - the fan kicked on as soon as test one got going. Actually, I kind of prefer it that way. You don't want units this size getting that hot, even at low loads. Extreme heat cycling from jumping from a low load to a high load every time you fire up SLI is kind of hard on parts. Seasonic? Change not a thing on the fan controller. Those who want silence aren't often shopping for 1250W units anyway. And at no time could I hear the fan over the screamers in the load testers, so it's not really a loud power supply anyway
It depends from our water cooling setup
(if it big and cool, it will be near to silent even under stress tests
Now i'm glad that bought not X-1250 but Platimax 1500 - after changing its fan to Kama Flex SA1325FDB12H (max ~1600 rpm and original fan was 900-2000 rpm), it's pretty silent now for 1,5 kW (but still not ideal - better only two PSU's).