The question above is for a standalone executable. I have read that on Linux the recomended way is to use an Apache Web Module. Would a Apache Web Module improves performance over Indy on Linux?
In theory you can expect a better performance on http.sys than Indy simply because we have optimized the http.sys with more care, and we don't control Indy source code.
But this is just theory. We haven't profiled both in same conditions to have real numbers. That's the only way to give you a correct answer.