7 Python libraries for parallel processing
Python is long on convenience and programmer-friendly, but it isn’t the fastest programming language around. Some of Python's speed limitations are due to its default implementation, CPython, being single-threaded. That is, CPython doesn’t use more than one hardware thread at a time.
And while you can use Python's built-in threading module to speed things up, threading only gives you concurrency, not parallelism. It’s good for running multiple tasks that aren’t CPU-dependent, but does nothing to speed up multiple tasks that each require a full CPU. This may change in the future, but for now, it's best to assume threading in Python won't give you parallelism.