You know, this [1] really ought to permanently put away the idea I think you're trying to reference, which is that only "event based" systems can be performant. There's plenty of "thread" or "process" based approaches that do quite well, including I believe the uppermost tier of every benchmark on that site. The idea that threads or processes are intrinsically slow was sheer unmitigated propaganda, and probably not only failed to contain a grain of truth, but are actively false. (Some thread implementations were slower than others, but that turns out to have been the implementations rather than the idea.) Event based systems inevitably have a lot of function calls in them, and that will probably in the end be slower than properly done threads or continuation-based approaches, always, because of that overhead.
[1]: http://www.techempower.com/benchmarks/