The first graph will showcase the Idle temperatures, which show everything is running smoothly. Under, you will find the graph for load-temperatures, since these matter the most. Lastly, there's the noise - which showcases how much noise these coolers put out when they struggle to keep the CPU under.
For most end-users, opting to choose max RPM and have the cooler run like a turbine continuously is not an option. Instead, the auto options should be enough for almost every situation. Therefore, this is the graph with auto-settings on, the CPU under pressure - and how noisy the AIO gets.
Fractal Design's Kelvin S24 seems to take the cake and eat it, though the difference between it and the second AIO is only half a degree. In fact, it was a close competition for the top 5 coolers, tighter than I've expected.
It's clear silence and all-in-one coolers don't mix. The most silent AIO is clearly audible and several dB(A) over its air counterpart. Not only that, but the worst performer - Antec's H20 1250 has this loud droning sound at maximum RPM that you will hear even inside a noise-isolating chassis.