Making WordPress Faster: LiteSpeed Cache, Seraphinite Accelerator or WP Rocket?

You won't notice a slow website in your own office on a fiber connection. Your customers notice it, searching on their phones on the go. If they wait three or four seconds for the first view, they are often already with the next provider. And Google is watching too: the so-called Core Web Vitals feed into how a page is assessed.

WordPress has some catching up to do here. According to the Web Almanac 2024, only 40% of mobile WordPress sites achieve good Core Web Vitals, compared with 51% across all websites. The good news: with the right hosting, a properly configured optimization plugin and a few ground rules, you can close that gap in most cases.

In this article, I compare the three plugins I use most often in client projects and show what else matters.

What Google means by "fast"

Google measures user experience with three metrics. They are collected from real visitors, and a page counts as good when 75% of all visits meet the threshold.

Important for perspective: Google explicitly names the Core Web Vitals as a ranking signal, but not as the only one. Great content beats a fast but empty page. So loading speed is no substitute for good copy, it is the precondition for that copy being read at all.

Measure first, then optimize

Before you install a plugin, take a look at where you stand:

• PageSpeed Insights (pagespeed.web.dev) shows two things: at the top, field data from real Chrome users over the last 28 days, and below it a lab value with the familiar score from 0 to 100. Field data is what counts for Google. The score is a diagnostic aid, not a goal in itself.
• Google Search Console, "Core Web Vitals" report: shows which groups of pages have problems on mobile and desktop. After a fix, validation takes 28 days.

If your site has few visitors, Google provides no field data. In that case, the lab value remains your best guide.

The foundation: hosting and server

No plugin makes a slow server fast. A good indicator is time to first byte (TTFB): up to 0.8 seconds is considered good. If your site is well above that, start with your hosting.

This is what I check on every project:

• Current PHP version. WordPress recommends PHP 8.3 or later. PHP 8.2 only receives security updates until the end of 2026.
• OPcache enabled, standard with almost every good host.
• Object cache with Redis or Memcached, especially for online stores and sites with logins. It takes load off the database wherever the page cache must not apply, such as in the cart.
• LiteSpeed web server, if possible. It brings its own very fast page cache that works with the free LiteSpeed Cache plugin. More on this in my article Hostinger in practice.

The most important rule: one optimization plugin, not three

The most common cause of broken menus, blank pages and empty carts I find in other people's installations: two cache plugins running at the same time. All three vendors agree on this. WP Rocket states that two caching plugins at once are not possible and explicitly lists LiteSpeed Cache as incompatible. LiteSpeed itself puts it this way: duplicated functionality slows your server down at best and breaks your site at worst.

So decide on one plugin and turn off caching and optimization in all others.

LiteSpeed Cache: the free choice for LiteSpeed servers

With more than 7 million active installations, LiteSpeed Cache is the most widely used plugin of its kind, and it is free for good.

Strengths

• The page cache runs directly in the web server rather than in PHP and is correspondingly fast, including dedicated logic for WooCommerce.
• Extensive feature set: image optimization with WebP and AVIF, lazy loading, combining and deferring CSS and JavaScript, database cleanup, object cache.
• Additional services via QUIC.cloud (critical CSS, image optimization, CDN) with a free monthly quota.

Limitations

• The actual page cache only works on a LiteSpeed server or through the QUIC.cloud CDN. On classic Apache or Nginx hosting, only some of the features remain.
• The many settings quickly overwhelm beginners, and the defaults don't get the most out of it.

Best for: Anyone whose host runs LiteSpeed and who wants a solid foundation without ongoing costs.

Seraphinite Accelerator: the most out of loading time and PageSpeed

Seraphinite Accelerator is less well known but one of the most thorough optimizers for WordPress. On wordpress.org, the plugin has a rating of 4.8 out of 5 stars across more than 50,000 active installations.

What makes it stand out

• Staged JavaScript loading: scripts are loaded in several steps, so the page is visible and usable right away. This is exactly where many WordPress sites struggle most, especially with page builders and tracking.
• Automatic separation of critical and non-critical CSS, so the visible area appears without delay.
• WebP and AVIF are generated on your own server, without sending images to a third-party service.
• Lazy loading for images, videos, iframes and fonts, plus a separate cache for the cart and logged-in users.
• Runs equally well on LiteSpeed, Apache and Nginx.

Free or premium?

The free base version offers a page cache, compression and browser caching. After 5,000 page views per month, however, it stops optimizing and only caches. For a business website with regular traffic or a store, the premium version is therefore the sensible choice: it optimizes without a page view limit, runs heavy optimizations in the vendor's cloud and comes with priority support. There is a 30-day money-back guarantee.

What to watch out for

• On a LiteSpeed server, caching and all optimizations must be turned off in the LiteSpeed Cache plugin; the vendor recommends removing that plugin entirely. Seraphinite can clear the server cache itself if you enable it.
• The first optimization pass uses noticeable CPU. On very small shared hosting plans, that can hit limits.
• The settings are extensive. The defaults usually work well, but fine-tuning benefits from experience.

Best for: Sites that should be at the very top on Core Web Vitals, and anyone whose host does not offer LiteSpeed.

WP Rocket: the easy all-rounder

WP Rocket is a paid-only plugin, known for delivering good results right after activation.

Strengths

• Very easy to use, sensible defaults.
• Page cache with preloading from the sitemap, delayed JavaScript, lazy loading and removal of unused CSS.
• Detects the likely hero image and excludes it from lazy loading.
• Supports LiteSpeed servers and clears their cache automatically, without the LiteSpeed plugin.

Limitations

• No free version. A license costs from $59.95 per year for one site, plus taxes.
• Removing unused CSS runs through an external service operated by the vendor.
• No built-in conversion to WebP or AVIF; that requires an additional plugin.

Best for: Anyone who wants a quick, uncomplicated solution and doesn't want to spend time on settings.

The three compared

What makes the biggest difference without a plugin

An optimization plugin can only improve what it finds. These points often have more impact than any setting:

1. Prepare images properly. Don't upload 5 MB photos straight from the camera. According to WordPress, AVIF files are up to 50% smaller than JPEG, and they have been supported since WordPress 6.5. The hero image at the very top must never be delayed by lazy loading.
2. Keep fonts lean. Load only the weights you actually use, in WOFF2 format and from your own server. In the German-speaking region, locally hosted fonts are the cleaner option for data protection reasons anyway.
3. Review third-party scripts. Chat widgets, tracking, embedded maps and videos are the most common slowdowns. Remove what nobody uses and load the rest only when needed.
4. Cut plugin ballast. Every plugin brings its own code. Deactivated but installed plugins should be deleted, and autoloaded options in the database should stay below 800 KB. Since version 6.6, WordPress warns you in Site Health when they exceed that.
5. Use page builders deliberately. Elementor, Divi and the like generate more code than a lean theme. That doesn't have to be a problem, but it calls for careful optimization.

My recommendation

• Your host runs LiteSpeed and the budget is tight: LiteSpeed Cache, properly configured.
• You want the most out of loading time and Core Web Vitals: Seraphinite Accelerator (affiliate link) in the premium version, on LiteSpeed hosting with LiteSpeed Cache disabled.
• You want a simple solution without fine-tuning: WP Rocket.

And regardless of your choice: measure before and after, and don't change everything at once. That way you can see what actually works.

Rather have it done for you?

I have been optimizing WordPress websites and online stores for fast loading times for more than 15 years, from hosting and plugin settings to images and fonts. Get in touch and I'll take a look at your site, free and without obligation.