Google says that they use the performance of your website as part of your search ranking:
You may have heard that here at Google we’re obsessed with speed, in our products and on the web. As part of that effort, today we’re including a new signal in our search ranking algorithms: website speed. Site speed reflects how quickly a website responds to web requests.
Speeding up websites is important ” not just to site owners, but to all Internet users. Faster sites create happy users and we’ve seen in our internal studiesthat when a site responds slowly, visitors spend less time there. But faster sites don’t just improve user experience; recent data shows that improving site speed also reduces operating costs. Like us, our users place a lot of value in speed ” that’s why we’ve decided to take site speed into account in our search rankings. We use a variety of sources to determine the speed of a site relative to other sites.
Here are more good reasons why speed matters:
Speed is among the most significant success factors web sites face. In fact, your site’s speed directly affects your income (revenue) ” it’s a fact. Some high traffic sites conducted research and uncovered the following:
Google.com: +500 ms (speed decrease) -> –20% traffic loss 
Yahoo.com: +400 ms (speed decrease) -> –5–9% full-page traffic loss(visitor left before the page finished loading) 
Amazon.com: +100 ms (speed decrease) -> –1% sales loss 
A thousandth of a second is not a long time, yet the impact is quite significant. Even if you’re not a large company (or just hope to become one), a loss is still a loss.
So how do you speed up your WordPress website to get that extra edge in search rankings and give a better experience to your users? Well you install a caching plugin of course! However not all caching plugins are created equal. For years WP Super Cache has been my weapon of choice because it is simple to install, very fast and is being constantly developed and improved.
One thing always annoyed me though, when I ran any of the performance analysis plugins like Page Speed and YSlow in Firefox or the built in Webkit developer tools in Chrome and Safari, my sites still weren’t scoring top marks even though caching was fully on. This really bugged me as I’m such a perfectionist! I just hated to see those red results in the Page Speed report.
Some of the things that always came up when I looked at the generated reports included:
- Make fewer HTTP requests
- Add Expires headers
- Compress components with gzip
- Use a Content Delivery Network (CDN)
- Configure entity tags (ETags)
- Use cookie-free domains
When I finally came across W3 Total Cache I knew I’d finally found the solution to all of this. After making the switch from WP Super Cache to W3 Total Cache I know I’ll be doing this for all WordPress implementations I do in the future. Don’t get me wrong though, for a simple low traffic site WP Super Cache is probably the way to go every time for it’s simplicity and the lack of technical skills required to install and get it up and running. However if your site has a lot of traffic or you want to improve your websites performance by an order of magnitude then I would recommend switching to W3 Total Cache. It requires a little bit more technical knowledge, but it is well worth it.
We were running WP Super Cache (fully optimised) on our site limbelabssolutions.com before switching to W3 Total Cache, the stats below speak for themselves.
This table was lost somewhere between upgrades between wordpress versions and moving to a static website (to improve page performance and site security)!
This could make all the difference to your server if you get a lot of traffic or want to be prepared for a sudden spike in traffic and of course improve your search ranking at the same time.
Here are the steps I recommend you take before installing W3 Total Cache, including some gotchas to watch out for.
- Benchmark your site before, during and after to understand the impact of your changes. There are many tools out there that you can use. I would recommend a combination of the following:
- Use Google Webmaster Tools, they have some nice stats on crawling your site, page load times and page sizes.
- Use the Page Speed and YSlow plugins for Firefox to profile your site.
- Safari and Chrome have a great Webkit profiler built into the developer menu.
- There are some online tools that you can use, some I like are www.showslow.com, www.webpagetest.org, tools.pingdom.com
- Remove all existing caching plugins AND delete them. I didn’t do this and it cause me endless problems until I realised what was going wrong.
- Install the W3 Total Cache Plugin, comprehensive instructions are here. Read them before you start as there are a few extra essential steps that differ from the norm and they will throw you if you don’t RTFM. Here’s a good tutorial on how to do it.
- I used our own simple Content Delivery Network, which was very easy to setup (see the the tutorial link above). One comment I would have on the CDN is that I wouldn’t host your minified CSS/JS on the CDN as they aren’t gzip compressed when served up, if you keep them on your main site then W3 Total Cache will serve them gziped. I’m running all this in a shared hosting environment, if I had a dedicated server I would have more control. You will also need to set your WordPress cookie domain in your wp-config.php file if you use this setup.
So there you have it, definitely use W3 Total Cache over WP Super Cache if you want to get that extra edge. However it is a bit more complicated to install and keep running.