How to shut OFF internal spinning drive if boot from SSD

[propower]

Hey all,

I can easily boot my 2013 imac from either a USB3 or TB SSD but I can't find any way to stop the internal drive from spinning! Put HD to sleep in Energy Saver doesn't do it no matter how long I wait. Un-mounting doesn't do it. Does any one know how to make this happen. I just want to make this machine as quiet as possible at times.

Thanks!

 

[joe-h2o]

How do you know it's running?

The whirring sound is the fan. As far as I can tell, the "put to sleep" option in energy saver works just fine for my iMac - I'm sure it does, in fact, since part of my iTunes library is on that drive (with the rest of it on the boot SSD) and if it plays a song that it has to get from that drive it needs to spin it up.

If you're sure the drive is permanently awake then you have something accessing it regularly enough to keep the spin down function from kicking in.

If it's unmounted and still making noise, then you're hearing the fan and thinking it's the hard drive.

 

[propower]

I know because I have two almost identical imacs - one with SSD one with spinner. It is definitely the HD .

I can also hear on boot the HD spin then the Fan kick on.


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Figured it out thanks!