No, that was just an example of a unexpectedly CPU-bound operation. My point was that you can't assume your Python program is not CPU-bound. Every time you have to do something non-trivial in Python, performance could become an issue.
From the perspective of a Python program, being memory bandwidth bound is the same as being CPU bound: you have the GIL, your process is in the running state in the OS, and is currently executing on a core.
(I assume you mean truly mean bandwidth between main memory and the processor, and not to disk.)
