Suddenly noisy iMac

[spinstorm]

I got my new iMac last Thursday and all day Thursday I didn't hear any noise coming from the iMac when it was just idling... during the night (I leave it on) it was almost entirely silent.

But since Friday night it's had the fan whirling away when idle and it literally is doing nothing. It doesn't seem to want to slow down.

I can't imagine why a quiet almost silent fan on the first day is now noisy... I did add an extra 16GB RAM in on the second day but that's all so why is it noisy mow?

 

[GGJstudios]

Use iStat Pro (free) or iStat Menus ($16) to get accurate readings of your temps and fan speeds.

Follow every step of the following instructions precisely. Do not skip any steps.

1. Launch Activity Monitor
2. Change "My Processes" at the top to "All Processes"
3. Click on the "% CPU" column heading once or twice, so the arrow points downward (highest values on top).
   (If that column isn't visible, right-click on the column headings and check it, NOT "CPU Time")
4. Click on the System Memory tab at the bottom.
5. Take a screen shot of the entire Activity Monitor window, then scroll down to see the rest of the list, take another screen shot
6. Post your screenshots.

If your fans are spinning faster without increased heat, try resetting the SMC.

 

[smoge]

I have a new iMac and I never hear a peep out of it! Sound very strange... I don't have flash installed, it mite be that be very unlikely if its idle. have you tried restarting? (generic answer to 99% of all issues)

 

[spinstorm]

I reset the SMC and the noise stopped... for about 10 minutes.

I can now positively say it is the hard drive that is making all that noise.

Even when idle.

It sounds like a constant write on the HDD - even when it isn't doing anything.

Any ideas?

 

[WrrN]

I reset the SMC and the noise stopped... for about 10 minutes.

Any ideas?

Did you get the Activity Monitor screen capture?
How about the iStat Pro app?
This info will help narrow the issue and GGJstudios knows things.

 

[spinstorm]

The noise has now stopped.

It was definitely the HDD, and then just as suddenly as it started it then stopped.

Now I only get HDD noise when I am actively using it, it is totally silent (except the very gentle whir of the fans).

Strange...