When you run the Python code (The Python “API” for the ADC), e.g. read(), it actually downloads an executable to the MicroBlaze processor. The executable runs on the MicroBlaze to read the XADC< and writes a result back to memory. The Python code then reads and returns the result.
There are a few ways you could speed this up depending on what you need to do, and your ability to write software/design hardware.
What are you trying to do?
Cathal