I'm running W3TC and WP latest, and other than the preload page cache problem reported earlier it seems to work well. But the biggest slowdown on my site happens in a random manner right after the browser connects, and (on Firefox) the status bar says "Waiting for [hostname]..."
This behavior occurs perhaps every dozen or so loads, can take between 5-30 seconds to clear, does not happen with particular pages, and seems to happen whether or not I'm logged in (W3TC is set to serve cached pages to non-logged in users only, though other cache settings may be involved). I'm on Bluehost Pro (which sped things up a bit), have checked CPU throttling/bandwidth and no biggies, and have checked mysql_slow_queries and no biggies. I have checked error logs, and there are only a few plugin errors, but one includes W3TC: w3_url_format() call generates a fatal PHP error...should I be worried about that one? (Full error at bottom.)
Recommendations for other ways to diagnose this maddening "Waiting..." error? I can't believe it's the server itself, and did not experience this before I installed W3TC, so I'm almost sure there's a setting somewhere I don't have optimized.
Thank you for your input!
[22-Sep-2011 14:53:09] PHP Fatal error: Call to undefined function w3_url_format() in /home2/envirolc/public_html/wp/wp-content/plugins/w3-total-cache/lib/W3/Plugin/PgCacheAdmin.php on line 213