So in answer to the question, "Is it possible to create fast games without using C++?", we hold up Eve online as an example that's written in Python, except that the fast parts (the rendering) are written in C++?Any particular game will have to interface with the operating system at some point. Chances are that interface will be written in... C++. That does not mean YOU have to write C++ to access it, as the interface may have been written for you. Python with PyGL or PyGame uses C++ (or C) at some level in order to access the underlying functions.
That being said, the majority of the C++ part of the eve graphical engine is mostly just wrapping up DX in a fashion to make it "usable" as a simple component of their core, python, engine (called Carbon).
I love using Eve Online as an example of a game written in Python, and I'm not saying it isn't possible to write fast games without C++ (it is!), I'm just pointing out Eve isn't the best example to use in context to the question of this thread. Unless I'm completely misunderstanding what you meant, which is likely.Eve certainly isn't the only game one can use as an example of a fast game that doesn't require C++. AI War, which is a .Net based game, used SlimDX as its core for rendering and input for a long while. It now uses unity as its core.