IMac very noisy

Question

a mid-2011 iMac, purchased new in June 2012, running OS X 10.7.5, very noisy. anyone else experiencing this? I was used to this same sort of sound when TimeMachine was running, but this is constant and quite annoying.

Answer 1

Here is the SMART status, obtained per your suggestion. (After verifying the disk, then verifying and repairing disk permissions, I followed the instructions in Disk Utility Help to select the disk and get info):
Name : Macintosh HD
          Type :           Partition
          Disk Identifier :           disk0s2
          Mount Point :           /
          System Name :           Mac OS X
          System Version :           10.7.5
          System Build :           11G63
          System Copyright :           1983-2012 Apple Inc.
          File System :           Mac OS Extended (Journaled)
          Connection Bus :           SATA
          Device Tree :           IODeviceTree:/PCI0@0/SATA@1F,2/PRT0@0/PMP@0
          Writable :           Yes
          Universal Unique Identifier :           0A79A0A7-0985-3CEE-BCAC-1F3F9EF54780
          Capacity :           999.35 GB (999,345,127,424 Bytes)
          Free Space :           720.34 GB (720,342,347,776 Bytes)
          Used :           279 GB (279,002,914,816 Bytes)
          Number of Files :           1,010,660
          Number of Folders :           243,095
          Owners Enabled :           Yes
          Can Turn Owners Off :           Yes
          Can Repair Permissions :           Yes
          Can Be Verified :           Yes
          Can Be Repaired :           Yes
          Can Be Formatted :           Yes
          Bootable :           Yes
          Supports Journaling :           Yes
          Journaled :           Yes
          Disk Number :           0
          Partition Number :           2
I might also add that, though I installed an additional 8 mg of DDR3 last week, the computer seems slower. I had rather expected more speed.