Nginx vs Varnish: Test Results of 7 Different Configurations

Can someone explain to me why Nginx is faster than Varnish with static assets?

I am assuming that this is because Nginx is faster at basic HTTP serving than Varnish. However, I am further assuming that if you have dynamic content served from a cache will always be faster than from the webserver; even if your webserver is super-fast you still have to wait for the page to be generated by your CMS, webapp, etc.

I ask because I am working on some blog software (http://github.com/may/yabe) and one feature I'd like to incorporate is super-fast page loads -- implemented via cache.

As the site will be .. "half-dynamic" -- new posts are added every day or so -- I would like to re-generate the HTML on every request, but cache the results for a few hours. I was planning to rely on Varnish, Squid, etc. to keep the load off my webserver.

Thoughts?

"Unix sockets are faster, but fall over at high load (important)"

Any idea why using Unix sockets would cause failures under load?