Harddrive thump

[n0de]

I have noticed that when the power saving feature "turn of hard drive" happens there is a loud "thunk" noise.

This blog: http://blogs.warwick.ac.uk/martingibson actually has a video of it occurring on a standard black MB as well.

Anyone have any idea what this is? Is it something to worry about? SMART status says there is nothing wrong....

 

[Sherman Homan]

Could just be the arm returning to its rest. In general, "thumps" are not good, but if this is consistent with the power saver and if it doesn't happen during normal use, then I suspect you are OK.
You do have a good backup in force, right?!