wd5000bmvw spinns at lower rate than normal ?

[raven4d]

hello .

i have got a wd5000bmvw-11amcs2 .
when plugged to linux machine , it gives "spinning up drive " and keep loading .

using a Stethoscope to hear what's going inside "i usually do to diagnose the movement of inner parts" i hear healthy spinning sound but the drive spins at a lower speed than the normal "compared with other similar drives"

i am suspecting the PCb motor ic , but liked to have a second opinion .

thank you