It's hard to beat a skilled CL person who invests in making something fast.
But Scheme code can often be made faster, especially if you know the performance characteristics of the particular implementation.
Besides generally using good performance practices, know that Racket has some profilers that can be immensely helpful. (I once rigged up Racket's statistical profiler at the time to capture the data for each instance of certain kinds of very complicated Web requests in a production system, and used the reports to optimize the heck out of it.)
But Scheme code can often be made faster, especially if you know the performance characteristics of the particular implementation.
Besides generally using good performance practices, know that Racket has some profilers that can be immensely helpful. (I once rigged up Racket's statistical profiler at the time to capture the data for each instance of certain kinds of very complicated Web requests in a production system, and used the reports to optimize the heck out of it.)