Just wanted to see if anyone else has this perception and with what disks. The noise from my system is dominated by the Samsung HD501J hard disk which although soft-ish mounted seems to be a very vibration prone sample. What I have noticed is that there is subtantially more vibration and hence noise when the hard drive is cold. Typically after switch on for about 2-3 minutes this is the case and gradually improves over time. This is not so much about seek noises but more from 7200rpm motor vibration. I can tell it is vibration as sometimes on a cold start it is enough to set the side panel vibrating badly and it gradually dies down. Maybe the bearings have an optimum temperature range?

I did search and found nothing similar but I do wonder if anyone else is familiar with the phenomena? Is it another reason why overcooling a hard disk might be bad?

This is completely subjective, and more than likely has something to do with the human senses adapting, but I've had the same experience with drives over the years. The motor/disc spin vibration and seek noises seem to be rough at first if a drive starts off in low ambient (+16...+18 °C in the old house), and then smooth out over the next 30-60 minutes.

The Maxtors of yore (talking first-generation FDB here) were especially bad at dealing with low temperatures, if memory serves - they would audibly clack and whirr until they warmed up. A similar effect could be perceived in the Seagates I owned at the time.

There is no doubt an optimum temperature for everything, but what that is for hard drives (and their components) is subject to debate. Manufacturers only tend to offer Operating and Non-operating temperatures, but AFAIK have not offered recommendations in drive specifications for optimum temperature. Makes sense, as then the drives won't have to comply with as strict a temperature range, and can appear more rugged or multi-purpose on paper.

In situations where the drive mounting has a little bit of soft material, that can also change its dampening properties a bit when heating up. Same goes for el cheapo metal mounts if the steel is thin enough. With resonating frequencies it doesn't take much to make a difference. A bit like sticking a folded piece of paper under the leg of a wobbling table.

That's a good point - it's not just about the material(s) of the drive. Tools and materials I've used have behaved quite differently as their temperature has changed, although my experience mostly applies to drastic changes (like winter outdoor ambient vs house ambient).

What I've found with my HD501J soft mounted is that it is most definitely not a perceptual thing. The soft mounting is only very short due to how I've had to mod the standard bays in the SG03 and I think the heavy vibration initially is enough to get through the soft mounting whereas later it isn't. The air born whirring is difficult to tell if it is louder or not but with this system if I leave the side panel slightly loose, on startup it'll rattle like crazy and then die down within 1-2 minutes. Fitting the side panel properly obviously solves this but it's just to prove a point.

Just to clarify: I prefaced as I did since my experience is from long ago, and it was only meant to apply to me personally. I haven't noticed any of this in the later years with improved WD drives and better cases.

Loud grinding noise is normally an indication of drive failure. It doesn't make sense that a brand new drive and an old drive would start grinding at the same time and only when cold.Hard driver louder sound like old drivers.

It's not a grinding though, this is just natural vibration being of greater amplitude when colder so I'm not worried about the drive failing.

the softmounts are probably expanding as the case's heat rises, gripping the drive tighter and minimizing vibration.

check the drive's noise levels laying it on a block of foam. i bet there's no noise differences between cold and hot then....