On Sun, 13 Jan 2019 16:14:36 -0500, Paul
wrote:

Peter Jason wrote:
I have isolated an SSD because it was very hot to
the touch (others are barely warm) and this has
fixed recurrent "scan/repair disks" flags in the
RHD notifications screen. Is this characteristic
of failing SSDs?

An SSD could be hot, because it did not receive
any cooling air. Some laptop drive bays are almost
completely insulated, and there is no airflow.

Sometimes, a laptop with such a design, ships with a
5400 RPM drive in it. Specifically, because the manufacturer
knows the bay is "power limited" and a higher performance
drive will overheat in there.

*******

The drive could run hot, as a function of the
"level of activity".

M.2 drives (running at up to 2500MB/sec), tend to hit
thermal limits more than conventional SATA SSDs (500MB/sec).

CMOS power dissipation is a function of FCV^2. And F is the
toggle frequency (as an output toggles between 0 and 1 and
back to 0 again.

We can't tell exactly what the SSD drive is doing all
the time, as it has its own processor and background
maintenance processes.

The spec sheet for the drive lists various power specs.
Like, how much power it draws on a write, and how
much power it draws when (nominally) idle.

If you had a clamp-on DC ammeter, you could measure
the current flow on the +5V wire of the SATA power cable.
Maybe a drive I have here, draws around 500mA max (as the ones
I've checked, seem ready to use with USB ports). Using your
clamp-on DC ammeter, you can measure the current flow and
get some idea whether the device is radically outside
of norms or not.

A ceramic capacitor could fail short, or a solder joint could
have a shorted solder connection, and that might
make something hot. That kind of thing has been seen
on DIMMs before, and it's a bit weird, as the DIMMs are
supposed to receive a quick test before they go into the
package. But if the drive is uniformly hot, it could be
that the drive has no air cooling. If the drive only
dissipates 0.15W at idle, it's going to be pretty hard
to raise the casing to 60C that way.

If you have a Kingston SSD, those use SandForce controllers
that compress write data and decompress read data. And that
burns up more power than drives that don't compress. The spec sheet
for the drive, should reflect that extra power usage.

Paul

Thanks, it was a Samsung 750 EVO SSD about 18
months old. Are there super-grade (military
quality) SSDs available with longer life spans?
And are the SSDs that plug into PCE slots any more
reliable? I've always known SSDs to run cool.