Really, writing fast code is mostly down to the programmer. For example C is widely recognized as the fastest non-assembly language simply because it leaves a lot to the programmer, C won't magically make your terrible code fast, unless you are using time-to-segfault as a metric. Assembly is the fastest if you know what you are doing, very few know what they are doing.

So, what kind of code are you going to use for your benchmark? Highly optimized code written by experts spending way too much time, the "most idiomatic" code, code written by an average skilled programmer picked at random, code extracted from a big open source project? This can drastically change the ranking, so which one is the most relevant? If you go with the "most idiomatic" for instance, you miss out on the idea that parts can be optimized if needed, and that in real life, programmers aren't perfect and can write suboptimal code by mistake.

There is also a cultural aspect to languages that may not be caught in benchmarks. For example, C programmers tend to have a culture of performance, they tend to know about their hardware, will try to save memory, make data structure efficient, etc... Python programmers, not so much, instead they tend to value readability and development time.

You can't test languages like you test CPUs for instance. With CPUs, you just run the same code on them and time them. You can't do that for obvious reasons: your C compiler won't accept your Python code, it is necessarily an apples to oranges comparison.