Can you make a great first impression in less than two seconds?
Okay, you as a person could likely pull that off. But can your website? Are visitors already reading your content by second two, or still waiting for the navigation to load at second five?
Fast WordPress performance can be the difference between earning a visitor’s attention and sending them to a competitor. Modern consumers expect lightning-fast sites, even—especially—on mobile.
A one-second delay in response time can reduce website conversions by 7%. And over half of online customers say that site slowness is the top reason they would abandon an action.
WordPress is fully capable of making a good first impression. But fast performance requires monitoring, optimization, and top-quality WordPress hosting to keep improving.
This page covers everything from the basics to the advanced steps you can take to improve WordPress performance. Here’s how to make every second count.
The Fast WordPress Fundamentals: The Four Laws
Every WordPress site is unique. There are different infrastructures, configurations, and endless combinations of plugins that can impact performance. That said, there are a few foundational truths for any and every WordPress site.
We’ll get deep into the details further down the page. But before we start, it’s important to understand the underlying principles of WordPress optimization.
WordPress Is the Smartest (and Slowest) Thing in Your Stack
You know WordPress is the Swiss Army Knife of CMSes, capable of handling dozens of different tasks. But have you ever tried to open a can with a Swiss Army Knife’s can opener? It takes a week. Just because WordPress is technically able to do everything doesn’t mean it should. Part of optimization is finding the tasks that are a waste of WordPress’ computing power (more on that later).
Cache Optimization Is Key
Your database is the ultimate bottleneck. A great deal of improving your WordPress performance is handling requests before they ping the database. Caching pages and objects helps your site answer client queries without going through the bottleneck.
Hardware Is a Temporary Solution
You can see some short-term performance gains by upgrading your server, adding processing speed and power. But it’s a temporary fix if your site’s architecture is dragging down your speed. You can put a V8 engine in a car with square wheels — but you will see more gains by swapping the tires.
Great Performance Needs to Be Part of Your Process
Over time, even the most optimized sites will accumulate junk that slows down performance. It’s important to continually monitor, make improvements, and implement automated testing for new code.
Six Must-Haves for Fast WordPress
To understand how to fully optimize WordPress performance, think about everything that goes into making a winning race car. It takes a powerful engine, sure, but also aerodynamic design, spoilers, shock absorption, responsive steering...every aspect of the car is optimized for speed.
Here’s how to turn your site into a Formula One champion.
Updated PHP with Opcode Cache
Using an outdated version of PHP is like using a flip phone instead of a smartphone - it works, but it’s nowhere near as capable. PHP 7 is between 20 and 100% faster than 5.2. Keep your PHP up-to-date and use the built-in Opcache to reduce CPU load.
Persistent Object Cache
Reduce the load on your database and CPU overhead with either Redis (included in Pantheon accounts) or Memcached.
Reverse Proxy Page Cache
WordPress can serve cached pages, but other subsystems can do it up to 200x faster. A reverse proxy like Varnish not only helps with performance, but also can help your site be more stable during a traffic spike.
Solid State Drives (SSD)
This is the lone hardware suggestion on our list, but it’s well worth considering. With spinning-disc drives, there’s a physical limit to how fast data can be retrieved. It makes a notable difference in performance--that’s why Pantheon exclusively employs solid state drives.
The InnoDB Engine
Make sure your database can keep up with the SSD speed by using the InnoDB Storage Engine to avoid table-level locking. InnoDB also helps preserve your data if you have a crash.
Dedicated Search Index
Search is another function that WordPress can do, but not as well as an external solution. A dedicated index is more responsive and has extra features that WordPress’ default doesn’t have. We recommend ApacheSolr (bundled with Pantheon), but ElasticSearch is another solid option.
WordPress Performance Optimization: Easy Tweaks
Optimizing WordPress is a well that you can dive into as deep as your technical skill and attention span allows. If you’re ready to strap on the SCUBA gear, start with our Frontend Performance Guide.
But you don’t have to plumb the technical depths to make your site more responsive. There are plenty of easy wins just below the surface to achieve the best WordPress hosting experience possible. Here are eight quick steps you can take to add more pep to your site.
Optimize Image Sizes
Creating compressed thumbnails of .jpg files before you upload. For images with just a few colors, consider .png instead of .jpg for smaller file sizes. Use vector-based .svg files whenever possible, too—as text files they are often smaller than their binary counterparts.
Update to the Latest Version of WordPress
The most recent version of WordPress is fully supported, secure, and optimized for best performance. Make sure you stay on top of core updates, either through automated updates or a custom WordPress update workflow.
Go to Settings >> Discussions in your admin panel, select “Break comments into pages,” and select how many comments to display per page.
Display summaries instead of full text
If your blog’s front page takes forever to load, switch to a summary/”read more” format to make it load faster, and be easier for your readers to navigate.
Remove Unused Plugins, Themes, & Media
Take no prisoners when you audit your files and data. Plugins that duplicate functionality, themes you never used, the midi file of your corporate anthem--ditch them all.
Delete Post Revisions & Spam Comments
Old post revisions can double the size of your database, and spam comments don’t do anything but take up space.
Identify slow-running MySQL queries and replace them. Here’s a quick guide to using New Relic (included with every Pantheon account) to get started.
Top Tools for Debugging WordPress Performance Issues
The first two steps to solving a WordPress performance issue are 1) Identifying there is an issue, and 2) identifying what’s causing it. Either step can be challenging for complex sites.
We recommend these tools to help with your ongoing monitoring and optimization.
New Relic APM Pro
New Relic is a powerful digital intelligence platform that makes it easy to keep an eye on performance. We consider it an indispensable part of your site’s admin tools--so much so that we made it available for free to every Pantheon user.
Some performance issues only emerge when your website gets a surge in traffic. The unexpected nature of traffic spikes makes it hard to plan for them in advance. Blazemeter can simulate virtual traffic from around the world to help load test your site.
Lighthouse is a simple, easy-to-use page analyzer built into recent releases of Chrome. It can identify slow-running components, display statistics about the page, and offer suggestions for improving performance.
The aptly named Plugin Performance Profiler is a worthy addition to your toolbox, too. It simulates traffic to your site, analyzes load times, and identifies poorly-configured or otherwise performance-degrading plugins.
XDebug and Blackfire
Debugging and profiling are essential for maximizing your code and plugins’ performance. XDebug is a PHP extension that enables debugging and profiling capabilities. Blackfire is a profiling SaaS solution, with a limited free version and a subscription offering with more features.
Website Performance Monitoring 101
The Fastest WordPress Hosting
The right host can be a powerful ally for boosting your site’s performance--and the wrong one can hold you back. Look for a host that has performance optimization built into the platform. Much of the ongoing work of optimization and performance monitoring is easier if your host is a worthy partner.
Look for a management platform with these characteristics:
Scalable Container-Based Infrastructure: The right infrastructure can expand capacity on-demand, maximizing uptime and responsiveness without breaking your budget.
Databases Properly Configured by Default: Too many hosts sell nothing but empty server space, leaving stack design up to you. The right host will set you up for success out of the box.
Built-In Caching: Reverse proxy and object caching are major performance components. Your host should include both in their initial loadout. A global content delivery network (CDN) can provide reverse proxy caching so pages load quickly regardless of the request’s geographic location.
Easy Updating: Your host should make it easy to run the latest versions of PHP and WordPress core.
Developer’s Guide to Frontend Performance
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