Incorrect sensor reading ?

[Magnum]

Has anyone else discovered that the S.M.A.R.T. readings for the hard disk temperature are bogus ?

Evidence

Temp with laptop on desk = temp of laptop 4 inches up with a fan cooler below it.

[MichaelW]

Such a simple test, performed without any significant knowledge of the heat transfer properties of the HDD/case/heat-pipe system (if one is involved), etc, is not conclusive.

[sinsi]

The trouble with SMART is that there is no real standard, each manufacturer does things a little differently.
There are a few settings that are (seem to be) universal, most are proprietary.
I have had two drives, in the same computer, at 0C and 150C  ::)

For proper SMART readings, get the diag program from the drive manufacturer.
I was going to write my own but there's not a lot of info about what's returned. 512 bytes of data, but what it means is secret stuff...
http://www.masmforum.com/board/index.php?topic=6010.0

[Magnum]

I understand that the test was real simple.

The hard drive is located on top of the bottom of the computer, so it transfer heat to it.

It's get so warm that it discolored the finish on a wood table.

With the fan going, the temp was brought down to close to room temperature.

But the sensor readings showed no change.

One of those mysteries.
Speed fan shows Temps of 75 F, 95 F, 113 F, and 77 F. (4 sensors on hard drive ?)

HD0 shows 88 F which I think is probably a weighted average.

[Magnum]

It looks like the sensors do in fact work, but they are very,very slow about reporting new values.

With no fan going underneath the laptop, temp was 97 degrees F.

With fan going, it dropped to 88 degrees.

Nine degree drop sounds pretty decent.