About a month ago I started trying to cut down the page load time on my site, which at that time was running Wordpress + W3TC + APC cache + Rackspace CDN on a dedicated server.
Back then I made a post here outlining the relatively slow time to first byte (~1+ seconds) and start to render time (~2+ seconds) http://www.webpagetest.org/forums/showthread.php?tid=3555&pid=7529#pid7529
Apparently the issue is that W3TC somehow was not caching the database requests as it should be doing and that every page request therefore had to make a lot of calls to the database which slowed TTFB times.
I tried to find a solution to this, even posting about it in Wordpress’ Support Forums (http://wordpress.org/support/topic/w3tc-database-not-cached?replies=4) but sadly there were no replies and I couldn’t get W3TC to cache the page properly, even after spending days reading the support forums and the W3TC installation documents.
Afterwards I sort of gave up and left thing running the way it is.
Today it occurred to me that there is another caching plug-in, that is the WP Super Cache that is less popular than the W3TC. It didn’t offer the same multiple functionalities as W3TC. For instance, I need to install a separate minify plug in (WP-Minify) and a CDN plug in (CDN Sync Tool) where in W3TC these features are all covered.
However to my surprise WP Super Cache works very well and now my TTFB is very fast at around 0.3 seconds (down from ~1.5-1.7 seconds: http://www.webpagetest.org/result/111007_2Z_1TM5H/ ) and the start to render time is now at 0.9 to 1 seconds (down from ~2.5-2.7 seconds).
First View Time from Dulles improved from ~5.5-5.7 seconds to a high 3 seconds now. With repeat views down to 1 seconds and sometimes under 1 second.
At the same time First View Time from London improved to 5.3 seconds (it was around ~8+ seconds before). FYI the server is in Las Vegas.
I’m very happy to report these findings. Anyone else with the same issue I had can give WP Super Cache a try to see if it improves their situation.
Some things are still not working properly with WP Super Cache, for instance I can’t get the minify and CDN feature working together as the css file would not load properly, but for now I’m very happy as the site is loading at a much faster time than before.