Don't forget taking into account browser buffering: depending on which one
you are using, it waits for a certain amount of data before displaying
anything.
To convince you of that, listen to the incoming network traffic to check
that data is arriving to the client.

That's a limit upon you cannot do much.

To ensure configuration of the PHP part is done correctly, you can dump
communication between nginx and PHP.

With all that, you should be able to reach some conclusions.
---
*B. R.*
_______________________________________________
nginx mailing list
nginx@nginx.org
http://mailman.nginx.org/mailman/listinfo/nginx