Why only Samsung 970 Evo shows 3 temperatures?

[danilo72h501]

Good morning, I would like to ask if anyone knows why only the Samsung 970 Evo detects 3 sensors and not the Samsung 990 Pro. Thanks.

[Blacktempel]

It depends which sensors your NVMes will report.
As long as there is at least one, it should be fine.

There can be a couple of thermal sensors for one NVMe, but I have not yet seen one which uses all of them.

[danilo72h501]

The thing is, I also use traffic monitor with the HardwareMonitor plugin and it reads 2 sensors on all three of my SSD

[Blacktempel]

I have a lot of 990 Pros and mine also have two sensors (the sensor without an ID is basically the same one as Number 1) so it does seem a bit weird, yes.

You can check here if all of your thermal sensors can be detected properly:

https://github.com/Blacktempel/DiskInfoToolkit

Take latest release and start either "ConsoleOutputTest" for a log file in same directory (contains a lot of information about your detected drives) or "DiskInfoViewer" to display some data, but with a graphical interface.
Both will show in Smart Attributes the temperature value (in Kelvin).

[danilo72h501]

I was using the .NET 4.8 version, switching to the .NET 10 version all the sensors are detected.
Thanks

[drstonephd]

I looked this up one time because I was curious. I'm no expert so take this with a grain of salt. The memory and controller can have different temps. The controller can run much hotter by design. The temperatures a device can safely handle will vary by model. Sometimes there will be "composite" temperature. For consumer models the composite temperature might be just the higher of the two real temperatures. A simple max temp does not work for enterprise grade hardware. Enterprise monitoring requires an entirely different thought process. It would be a PITA to have to maintain a list of threshold temperatures by device. Some are designed to run hotter than others. This is were a standard composite defined on the device comes in handy. All devices report a single number that a monitor can use. (The single number accounts for varying temps and thresholds of all parts on the device.) The device also reports static WCTEMP and CCTEMP values the monitor can use for warning and critical thresholds. These don't have to be a real temperatures. There are also health bits a monitor can use to detect if these thresholds are reached. It's implementation specific, so you have to get the specs for your exact model to know what "temperatures" are provided. A composite, if provided, is the most relevant for monitoring and fan control. Now I'm curious if I can see a WCTEMP and CCTEMP on my SSDs.

https://nvmexpress.org/wp-content/uploads/NVMe-NVM-Express-2.0a-2021.07.26-Ratified.pdf

Composite Temperature: Contains a value corresponding to a temperature in Kelvins that
represents the current composite temperature of the controller and namespace(s) associated
with that controller. The manner in which this value is computed is implementation specific
and may not represent the actual temperature of any physical point in the NVM subsystem.
The value of this field may be used to trigger an asynchronous event (refer to section 5.27.1.3).
Warning and critical overheating composite temperature threshold values are reported by the
WCTEMP and CCTEMP fields in the Identify Controller data structure in Figure 275

Seems like I read about a composite temp that includes WCTEMP and CCTEMP in the evaluation so that one number applies across all devices. For example, 70C would be a warning for all devices even if their real temps varied from 50C to 100C to reach the threshold for the alert.

[drstonephd]

Cool! In HWInfo you can see the composite temp and thresholds. There is always just one temperature for each of my drives.

So, in fan control, the temp without the sensor number is the one to use. And the thresholds in HWInfo indicate what's too hot.

BTW Both my GEN5 SSDs have the same higher thresholds. This would mean a single curve for drives might require adjusting the GEN5 temps by about 5C down for the warning. And 2C down for the critical. This is a good example of why a single number for all drives using identical thresholds would be nice, even if not real temps.

[drstonephd]

Replying to myself.... (I don't talk to myself. Out loud anyway.) My drives power cycles is more than the power on hours. I don't turn off my PC that much. Appears to be controller resets or something.

[Blacktempel]

@drstonephd

HWiNFO in full mode seems to display only one thermal sensor.
If you start with Sensors only you'll see all thermal sensors for each NVMe drive.

LHM has both warning and critial temperature integrated, though not directly as SensorType.Temperature (this may change later), so they will not show up in FanControl list for thermal sensors.
There are even "default" values, based on standards suggestions, if none were set by manufacturer.
You can check this by starting LHM (take a master build from "Actions" tab) and going through your drives.

[drstonephd]

I used sensors only in HWInfo. I do see all temps. However, only my newer EVO 4TB drive has more than one temperature. The 2 new GEN5 drives show only one temp. The old, ancient EVO shows 1 temp. The external SSD shows one temp. LHM shows the same temps. Maybe more than one temp is becoming a thing of the past.

I could not find the warning and critical temps in LHM. Is this because the LHM display is limited to sensor values?

Is it a feature request to read the warning and critical temps? Can FanControl use the warning and critical temps to create a composite temp that applies for all drives? Is a normal idle temp required to make a composite temp for a single fan curve for all drives? Food for thought, perhaps.

PS Apparently, only the composite temperature is required in the NVME standard. Individual sensor temps can require proprietary commands to obtain.

[Blacktempel]

Did you check here ?

You also have to use a recent version of "Actions" tab - take a master build.

[drstonephd]

I don't have the "Factors" group in your display. I will wait for the release and give it a try.

Also, the external drive is not showing a temp. I thought it was. I must be confusing LHM with HWInfo.

[Blacktempel]

Try that one, latest master build as of now: https://github.com/LibreHardwareMonitor/LibreHardwareMonitor/actions/runs/19773647373
That has the sensors and also supports external drive temperature.