WordPress is a very popular CMS used for websites. Offering an intuitive interface to manage and update websites WordPress is justifiably popular. However, WordPress sites can be slow, which can harm conversions and search engine rankings. This article explores the most frequent performance issues with WordPress sites and offers some solutions.
Why Speed Optimize WordPress?
Site speed is important both for conversions and search engine rankings. Speedy sites have been shown to convert more visitors into leads (not to mention saving money on bandwidth). Google has been factoring in site speed into search results (and PPC page quality scores) for years now.
Common WordPress Performance Problems
Here are some common performance issues we’ve found analyzing WordPress sites:
- Too many plugins – probably the most common problem with slow WordPress sites
- Non-Wordpress optimized server – overloaded shared server hosting
- External widget slowdowns – widgets that call offsite resources cause uncertain delays
- Overweight content – sliders and multimedia are the big culprits
- Unoptimized themes – themes that make many calls, unused default content
- JQueryitus – multiple copies of JQuery, loaded off-site
WordPress Performance Optimization Tips
To speed up your WordPress site you need to streamline everything: plugins, server, themes, content, etc. The idea is to minimize the use of plugins and external resources and use as much native WordPress functionality as possible.
1. Minimize Plugin Usage
Too many plugins can slow down WordPress sites. Remove unused plugins and replace old ones with the latest versions (good for security as well). Ideally replicate the plugin functionality you want in native WordPress code or custom PHP. The fewer plugins you use on your site, the less chance there is of performance and upgrade issues. Plugins can also call external resources, which introduce uncertain delay by relying on external servers. You can use a plugin performance profiler (in a plugin of course) to see which plugins are slowing you down.
2. Use WordPress Optimized Hosting
One of the most frequent issues with slow WordPress sites is poor hosting. Oversold shared mass servers can cause long delays and TTFB for any type of hosted site. All purpose servers designed to work for any site are not optimal for WordPress. Move your site to a host with servers dedicated to hosting WordPress-based sites. You want lightly loaded shared servers or dedicated servers with plenty of resources to get the most out of your hosting. After moving an actual WordPress site we found first byte times improved from 6.7 times for Cable to over 500X for DSL users. First byte times went from over 60 seconds to 0.15 seconds on DSL on the new optimized host.
3. Use a Website Accelerator
There are a number of software and hardware products out there that speed up websites automatically. While not a substitute for manual optimization customized for each particular site they can go a long ways towards speeding up your site. Mod_pagespeed automatically optimizes content and servers to reduce page size and complexity and speed up start render and page load times. Our tests showed a 17% to 43% improvement in start render times with mod_pagespeed. Load times improved by about 1/3 with mod_pagespeed. Note this improvement was in addition to the hosting speed improvement.
- Install mod_pagespeed – Shows actual results from installing mod_pagespeed
- Benefits of Installing mod_pagespeed
- Use a Website Accelerator – Shows results from Radware’s Fastview product, which is particularly good at reducing the number of web page objects (by over 72% in this instance).
4. Use a WordPress Caching Plugin
In response to the need for WordPress speed, developers have created plugins devoted to speeding up WordPress. Two of the more popular ones cache content:
5. Localize External Resources
External widgets abound on the Web. Counters, statistics, ads, awards, these gizmos add off-site overhead that can block rendering of your pages. Even the mighty Google can slow down your pages, when we localized Google analytics we speed up page rendering by 13%. Use web page speed auditing tools to locate slow offsite resources.
6. Go Asynchronous
If you must display offsite content (ads for example) consider using iframes. Iframes
don’t block subsequent content from rendering on your page. You can also use the new HTML 5 async attribute (in addition to defer) to execute JavaScript files asynchronously as soon as they are available.
7. Crush Overweight Content
Sliders with unoptimized images and multimedia are two of the biggest culprits to page bloat. The average top 1000 page as of this writing was 1492K with 108 requests (source HTTP Archive). Automated optimizers like Mod_pagespeed, Radware’s Fastview, and WP–Smushit can remove the unnecessary fat from graphics, but for more savings use lossy optimization. Minify, combine and HTTP compress your JavaScript, CSS and HTML files to squeeze every last byte you can out of your textual content.
- Optimize Graphics
- WP-smushit – automatically optimize images losslessly within WordPress
8. Pare Page Themes
One site fits all themes that do everything under the sun can cause fat web pages and unnecessary calls for your server and even offsite resources. Instead opt for an optimized or customized theme that is lighter on resources and heavier on design. The fewer SQL calls you make to your server the faster your pages will be.
9. Optimize Your WordPress Database
Over time your WordPress database can become bloated from spam, unapproved comments, page revisions, unused tables, etc. You can automatically optimize your database with a plugin like WP-Optimize.
10. Optimize JQuery
JQuery is commonly used for fancy menus and other effects and can slow down your pages. Multiple copies of JQuery, unoptimized and unminified JQuery, and non-CDN Jquery delivery are some common issues. You can user Google hosted libraries to include CDN, parallelism and caching in your JQuery mix.
11. Lazyload Images
Lazily loading images loads only the images shown above the fold. As the user scrolls down the page the subsequent images load, speeding up page loads “above the fold.” You can do this automatically with JQuery Image Lazy Loading or a Pagespeed filter.
12. Optimize Homepage Speed
Finally, entire books have been written (Jakob Nielsen) about the importance of homepage usability. Your home page most likely gets the most traffic of any page on your site, so pay special attention to speed optimizing your home page for better usability, conversions and speed.
- Minimize database calls
- Minimize plugin use
- Manually optimize all home page content (JS/CSS/HTML/images/multimedia)
- Show a few headlines, no decks for blogs
- Keep it short and sweet (highlights not entire articles)
- Minimize external resources (social widgets for example)
- Localize external content to avoid offsite slowdowns
- Apply onsite page optimization techniques (JS/CSS order etc.)
- Profile home page performance to locate performance bottlenecks with speed tools (Dynatrace, Pagespeed, Webpagetest, Webpage Analyzer, etc.)
Conclusion
Optimizing WordPress is a matter of getting out of the way of WordPress. Make sure your site is on a WordPress optimized host, minimize the number of plugins, update old plugins and ferret out the slow ones and replace. Use server and WordPress performance modules and plugins to automatically optimize your content and its delivery. Use the free CDNs out there and minimize the use of slow external resources. Streamline your theme and SQL calls and manually optimize your content for maximum speed.
Further Reading
- Case Study: WordPress Theme Optimization
- This article tests the benefits of optimized WordPress themes and hosting. Switching to a fast WordPress theme and optimizing hosting improved page load time by 74% and start render by 83.4%.