this! If you are concerned about noise, do not buy a 1U unit. Small fans still need to move air. Since they are small the way to make up for this is to have

this! If you are concerned about noise, do not buy a 1U unit. Small fans still need to move air. Since they are small the way to make up for this is to have a lot of them and make them spin very fast. The faster they spin the more noise they make.