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

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.)