Review on Cooler ID-Cooling IS-40X V2 LGA1700/1200/115x/AM4 (92mm fan, 800-2800rpm, 46CFM, 14-35.2dBA, 100W TDP, 4-pin PWM)BOX by Stanislaw Sipko ᠌

Fits in a very small space, as its maximum cooler height is only 47 mm. The i5-4670 processor has been moved over from the primary PC (84 watts, according to the standard). The fan runs at 1100-1300 rpm at 35-40 degrees and is completely silent. When subjected to stress at temperatures between 65 and 70 degrees Fahrenheit, the fan speeds up to between +1700 and 1700 rpm, producing a faint hum. I opted to switch out the fan because the job requires complete stillness. Only the noctua nf-a9x14 comes in the same form factor (and the thickness of the fan in this case is 15 mm). I bought it for the cost of the whole cooler, stood up "native-style," and there is now radio silence.