I've been having an issue when trying to use external sensor reporting (HWiNFO and GPUz) with TThrottle specifically regarding the GPU. I also have enabled my intel iGPU as there are some BONIC projects that can use it so I figure why not monter that as well, though I ultimately don't know if it really matters as I'm not sure where exactly on the board the sensor reading is actually coming from.
WHen using HWiNFO, I will have the option to select both the iGPU and dedicated GPU as separate entries in the drop down list. However the problem I have noticed is that every so often TThrottle will start displaying erroneous temperature data in the hundreds or even thousands, despite in HWiNFO the readings still being correct. I've found I can fix it by doing a recalibration, but it is only a matter of time before it goes haywire again so I can't trust or rely on it.
Meanwhile for GPU-Z, while I can switch between the iGPU and dedicated GPU in the program itself. In GPU-Z it will only display one option in the drop down list (2 - GPU Temperature), even if I am running two instances of GPU-Z and set each one to a different GPU.
I assume it is only the dedicated GPU temperature that it is seeing, but based on the name I can't be certain.