New builds will sometimes have weird smells (oil burning off in PSU, thermal grease breaking in) and some flakes from installation due to you installing stuff, and from moving parts shedding particles on them.
The latter should be much less if you use higher quality components, the former will may occur with any PC.
If it's persistent, then it may be a sign you have some moving part grinding somewhere which would be bad.
I am using quality components, and so I think they are due to installing stuff. I hard my case open the other day and I think I could see maybe 3-5 of them, if the light was falling just right. I don't think I have any any grinding parts: all my fans and PSU sound fine.
I guess my main concern is not that something is grinding, but more that something will short out... Should I be worried, or is this just new build jitters?