Normal
Something that won't get captured in simple charts with db levels is the kind of noise that gets made. One thing about any water cooling solution (AIO or custom loop) is that you must have a pump running at all times. Depending on the kind of pump, how much air is in your loop, what orientation its installed in, etc can affect the sound that it makes. Some people find pump noise to be more annoying than some fan noises, although fan noise can be all over the place and varies from fan to fan (40mm fans make a much higher pitched sound than a 140mm fan).If your main concern is idle noise, you don't just want to solve for the quietest but also the kind of noise that is least distracting/most pleasing to your ear.
Something that won't get captured in simple charts with db levels is the kind of noise that gets made. One thing about any water cooling solution (AIO or custom loop) is that you must have a pump running at all times. Depending on the kind of pump, how much air is in your loop, what orientation its installed in, etc can affect the sound that it makes. Some people find pump noise to be more annoying than some fan noises, although fan noise can be all over the place and varies from fan to fan (40mm fans make a much higher pitched sound than a 140mm fan).
If your main concern is idle noise, you don't just want to solve for the quietest but also the kind of noise that is least distracting/most pleasing to your ear.