In this talk you'll see an update to the Pyjion project, a JIT compiler for CPython byte-code. This project was started 5 years ago but stopped after making no gains in performance. Recent changes to CPython have made optimisations more viable, so now it has been restarted and is showing big performance gains vs. standard CPython with 100% compatibility. Many attempts have been made to build a general purpose JIT for Python and few have succeeded. Is it worth it and what are the gains to be made? This talk will cover the design ideas of a JIT for CPython, optimisations, and future potential.