I have a new i7 iMac with both SSD and internal drive. Everything seems fine with the system except it's making more noise than I'm used to. I have an existing 24" iMac, the version with the 2.8GHz "extreme" C2D processor and that runs effectively silently. The new iMac is making a sort of throbbing noise with a frequency of about a second. It's fairly quiet but is noticeable in an otherwise silent study. Is this normal on the new models and is it something I should be concerned about? Other than that, and a small speck of dust behind the glass, the machine seems to be free of the other issues mentioned in these forums.