usually always in speed and memory. C/C++ outperforms both of them, Rust as well. But maybe you want to use Elixir because you want a functional paradigm.
you should check for "what is my usecase / my problem domain" and "what do I gain / loose by choosing A or B" .... without metrics and a problem to solve this is taste and random benchmarks. :)
Do you know node ? stick with it, learn go on the side .... because what is "performance" when you cannot understand the language ? Statically typed languages are mostly developing slower so if you need fast release cycles a RAD language like node is preferable .... anyhow you see there are a lot of factors to consider and performance should be the least in the beginning.
Unless this is not a business decision but private curiosity than I would definilty pick GO to me it's the better designed language, but I prefer signature based contracts and such behaviours in languages.