Yes and no, I still remember the times when several Ruby on Rails apps I consulted for had 5ms DB queries and Rails' ActiveRecord was taking 120ms. Technically

Yes and no, I still remember the times when several Ruby on Rails apps I consulted for had 5ms DB queries and Rails' ActiveRecord was taking 120ms. Technically choosing C++ over Python will save you several orders of magnitude more than nanoseconds. Though C++ might be a bad example. I'd replace Python web app with Elixir or Golang.