missing sensor


recently found out about one more sensor inspiron 5576 has while tryin out siv64 tool:

Item Name         Current   Average   Minimum   Maximum   Samples  Item Name  Current   Average   Minimum   Maximum   Samples

  T2 ACPI OTPC     44.0°C    43.0°C    39.0°C    46.0°C       370
  T3 ACPI VGAT     41.0°C    40.2°C    35.0°C    44.0°C       ...
  T4 ACPI SYST     46.0°C    45.0°C    42.0°C    48.0°C       ...
  T5 ACPI DIMM     43.0°C    41.0°C    35.0°C    44.0°C       ...
  T1 ACPI DTS1     36.0°C    41.4°C    31.0°C    57.0°C       ...
  GPU-0 Temp       36.0°C    41.0°C    31.0°C    57.0°C       ...
  GPU-1 Temp       39.0°C    38.0°C    34.0°C    42.0°C       ...

[  OK ]  [ Copy]   [ Zero]  [Windows]  [Sensors]  [Status]   [Cooling]  [ Power]   [ SPD ]  [Volumes]  [ Main]

T1 ACPI DTS1 corresponds to EC CPU thermal reading in hwinfo
T3 ACPI VGAT corresponds to EC GPU (GPU-1) thermal reading in hwinfo
T4 ACPI SYST corresponds to both EC Temp4 and ACPI System thermal readings in hwinfo
T5 ACPI DIMM corresponds to EC SODIMM thermal reading in hwinfo
GPU-0 and GPU-1 temps correspond to hwinfo thermal readings in each of the GPU's dedicated section

T2 ACPI OTPC is not found in hwinfo. any idea what it represents?
tried to put GPU at max overclock and stress it for a couple of minutes - OTPC remained below 70C when GPU VRM overheated so it is likely not related to GPU VRM
tried to discharge battery to 85% and charge it at standard rate 32W - OTPC about 40C which is the same as in idle so it is not main systemboard MOSFET/charger sensor either
stressing CPU only with CPUburner OTPC goes above 55C, while stressing GPU only it goes above 60C, however running furmark on GPU and CPUburner with two threads at the same time OTPC reached 77C. it might be CPU/northbridge VRM related but more likely is some generic sensor on the board near the CPU/GPU area...
It might be a virtual sensor which combines multiple temperatures together (Overall Temperature), hence it's not shown among the DELL EC values.
OTPC is listed as an embedded method in ACPI info so i think it is a real sensor more likely than not. can you check why is not shown in DELL EC and try to add it there? from a short google search there are other systems with this method but nobody says anything about it. also Temp4 could be renamed to System
Your assumption is wrong. ACPI sensors are completely in hands of the BIOS, they can return any values including virtual or bogus ones.
alright. so even if it is virtual sensor it probably estimates values from two or more other important sensors, probably for fan control or system protection shutdown. just want to avoid running more than one app probing EC at the same time