My computer used to only have a single SSD, and to my delight it was completely silent. Now, however, I've added a pair of magnetic HDDs and the computer makes faint noise when idle. I'd like to stress that the OS and all applications are on the SSD, so I'd expect that when not accessing the secondary drives they'd be completely silent, but that is not the case - and I've just installed these, so I'd think no application would access them in the background.
Is there any way to make them completely silent as long as they are not accessed?