It seems like W3TC is doing a good job at speeding up my page loading. However, there is a huge delay before the page actually begins to load. It hangs around, "thinking", with a blank page, and then once the first byte is received it all loads pretty quickly.
With the page cache debug enabled, I saw this:
<!-- W3 Total Cache: Page cache debug info: Engine: disk: enhanced Cache key: www.mysite.com.br/_index.html Caching: disabled Reject reason: Cookie is rejected Creation Time: 6.003s Header info: X-Powered-By: PHP/5.4.4-14+deb7u2 X-Pingback: http://www.mysite.com.br/xmlrpc.php Content-Type: text/html; charset=UTF-8 X-W3TC-Minify: On -->
And also, with Firebug, I can see that the very first request (www.mysite.com.br) always gets a "200 OK" status, while a lot of the other requests get "304 Not Modified".
If I use a secondary domain that I have (www.mysite.tv for example) the page loads with 304s and I get no problems at all in the page cache debug info.
What could be causing that?