Now that Varnish is finally "the free version of a propietary software", it's time to look somewhere else, and the answer is right in front of our noses. When the word pripietary starts to appear, let's stick to the big guys. If you want to know how to get #2,000 requests per second without depending on anything else but your current webserver (yes, the same one you are using to serve your pages, no need to setup anything else here) then keep on reading.
In this article I will try to find out if there is any performance lead in running Drupal on IIS over Apache. I will not run any benchmarks on my own (for the moment), just analyze what I could find about this surfing the web. Type "iis vs apache drupal" in Google and this is what I found.
Date: Mid 2012
This post is outdated.
A new post has been updated with specific instructions for Drupal 8 and PHP7 here