I also agree with bwv848 and would back up your data immediately, the most important data being first, before doing the test. Doing the HDD test could send the drive over the edge. You have over 3000 pending sectors marked for reallocation. These are sectors that cannot be read and are awaiting reallocation when they can be read. This is very bad number. You also have a very large G-sense count which means the drive has been jarred enough to set off the sensor, increasing the count.
Current Pending Sectors
Count of "unstable" sectors (waiting to be remapped, because of unrecoverable read errors). If an unstable sector is subsequently read successfully, the sector is remapped and this value is decreased. Read errors on a sector will not remap the sector immediately (since the correct value cannot be read and so the value to remap is not known, and also it might become readable later); instead, the drive firmware remembers that the sector needs to be remapped, and will remap it the next time it's written.
However, some drives will not immediately remap such sectors when written; instead the drive will first attempt to write to the problem sector and if the write operation is successful then the sector will be marked good (in this case, the "Reallocation Event Count" (0xC4) will not be increased). This is a serious shortcoming, for if such a drive contains marginal sectors that consistently fail only after some time has passed following a successful write operation, then the drive will never remap these problem sectors.
Edited by JohnC_21, 29 December 2017 - 03:45 PM.