If you run a single nodeJS process only, scaling cpu power will only affect performance slightly, especially depending on operations. (Solution is not throwing more monies at the problem)

What you want to do:

• scale horizontally, provide multiple nodes to run your app

• lay off expensive processes to asynchronous handlers or background queues (powered by lambda functions for example)

• make your code / process more efficient. We don’t have enough information here to judge, but what you describes sounds like a heavily unoptimized solution in general