WD Green 500Gb ( Part number: WD5000AADS-00S9B0 )
When it was new - it was completly silent in noaction and silent in seek.
Today when it is work it’s still silent. It is very silent in low load. But at no load, after it parks by IntelliPark, it is not silent - it has some sound like seek in very short range, but it is slightly different and louder.
Also It has this sound in sequental read at the end of disk. It starts from LBA 440Gb At become louder till LBA 500Gb.