Z270 K6 BIOS Setting for Watercooler

Oh no, that is exactly what you should have gotten, the stock corsair fans are LOUD when they ramp up. Don't let anyone tell you that you can have performance cooling and quiet operation, its either mediocre cooling and quiet or good cooling and loud. The common misconception is that water cooling is quiet, it isn't, especially not with AiO coolers. Now a full custom loop with dual 360mm radiators equipped with silent fans will get you both good cooling and quiet but you are looking at a much larger cost and self assembly which I would absolutely not recommend to the average user. 1 leak and your system dies with custom loops. If done correctly that almost never happens but given "some assembly required" it isn't something for the amateur builder  

The trick with AiOs is to set your fans on a custom fan curve. This will allow for almost silent operation at idle - near idle and solid cooling when you have had a game running for 10mins or more.

As I suggested for your 120mm AiO, set a custom fan curve (you can use corsair link or ASRock F-Stream) for your fans that has them set to 0% at 20c with a straight line up to 100% at 60c. With these settings you should get the optimal quiet vs performance.

%

100 +

90      /

80     /

70                                   /

60                               /

50                            /

40                         /

30                      /

20                   /

10     /

0 +

0 10 20 30 40 50 60 70 80 90 100 C

This is what I set my AiO fans to and it only gets loud after about an hour of gaming.