Gpu-Z Temperature Sensor Questions

I am going to make this as generic as possible so to help future searches for a concrete answer. I spent over an hour searching google and forums attempting to find an answer.

Here is a capture of my GPU-Z sensor readout:

What/where are the different sensors that give these different temperature readings?

• GPU Temperature
• GPU Temp. #1
• GPU Temp. #2
• GPU Temp. #3
• VRM Temperature #1
• VRM Temperature #2

I know with CPUs there is the core and socket temperatures, is that the case with GPUs as well?

Thanks!