background noise of constant frequency
Since new (early this year) my iMac 27 iCore7 makes a constant noise in the background (not linked to disk activity).
It sounds a bit like a noisy power transformer, or could be a fan revving noisy, but with continuous speed. iStat doesn't show anything special in terms of temperatures or fan speeds and when these vary the noise isn't changing.
Noise vanishes when I put my Mac on sleep and resumes when I wake it up.
Anyone else experiencing this ?
Thanks for advice.
Is this a good question?