system
Given the following post, respond as if you're commenting on Reddit:
human
If every language is eventually compiled into the most basic machine instructions then why do languages like C and C++ run faster than Java and Python?

I don’t understand why lower level languages run faster than higher level ones if they are all eventually compiled into machine code.
gpt
First of all, you should distinguish between a language and its implementation(s). How and whether code in a language is translated to machine code can and does vary widely between different implementations of a language. For example the Python implementation PyPy has a JIT compiler, but CPython does not.

> If every language is eventually compiled into the most basic machine instructions

This isn't true. Not every programming language implementation emits machine code (as mentioned above, CPython doesn't), nor does every language have at least one implementation that does.

Beyond that, it doesn't only matter whether machine code is generated - it also matters *which* machine code is generated (also *when* in the case of JITs). For example, a naive compiler for a dynamically typed language might generate type checks for every operations (while a more complex, optimizing compiler still wouldn't be able to avoid doing so in all cases) while a compiler for a completely statically typed language would have no reason to do so. Similarly virtual function calls will necessarily involve extra lookups that can't always be optimized away.

In addition, a language might use big integers as their default integer types, heavily feature reflection, or contain plenty of other features that tend to be costly to implement.

Even among implementations for the same language, performance can differ significantly, so it's not surprising that implementations for different languages with different features and requirements would have even more differences in performance.

And then there's of course the fact that some languages simply have more mature (and thus better optimized) implementations than others based on how long they've been around, how widely they're used, and how much performance is even a priority.