Speeding Up WordPress
Making WordPress run fast is a dream of many people. The bigger and better your site gets, the slower it can run. This is, sadly, a semi-unavoidable fact. There are some things you can do to speed up your site, however!
If you've already tried all the tricks in WordPress Optimization, maybe it's
Out of the box, WordPress does not have caching. Most people don't actually ever need any caching, however, so this isn't terrible. When you do, though, there are two primary ways about it: Server caching and Plugins.
The most popular plugin is WP Super Cache which creates a static file cache of your site and loads that instead of using PHP to generate the page. If you're on shared hosting, this is the best option.
If you're on a VPS, though, you may already be using some server caching, so you'll want to try W3TC which still makes the static files, but also it can tie in with server caching to speed things up even more.
For all accounts we offer Pagespeed. Google Pagespeed is actually a cache! What it does is minify your files (make them smaller) and serve up those files instead of making WordPress process them. You can even optoimize it to the nth degree!
If you've used DreamPress, you'll know we have Varnish Caching on the servers, which is a great thing for non-logged in users. But we also have Memcached on those servers, to speed up things for logged in users.
Normal VPS users have X-Cache made available (just make it active in your server config and check a box in your domain setup) which (as mentioned) ties in with W3TC. If instead you want to self-install Memcached, try using the plugin Batcache to speed up WP.