Caching plugins are often the first line of defense when it comes to WordPress performance optimization.
But while most people focus on page speed scores and load times, there's one metric that gets overlooked far too often: CPU usage during optimization.
High CPU consumption can choke shared hosting plans, slow down your site, and even lead to server timeouts, especially during cache warmup or preload phases.
So, how do the top caching plugins stack up under pressure?
Let’s find out.
Test setup
To keep things fair across the board, we set up a test environment that reflects what you'd typically get with a basic shared hosting plan. Nothing fancy. We used 1 CPU core and 2GB of RAM, which is pretty standard for a lot of entry-level websites out there.
- Hosting environment: 1 CPU core & 2GB RAM (typical shared hosting spec)
- Test scenario: Cache preloading 20 pages per plugin
- Measurement: Peak CPU usage during active cache population
CPU usage results
RabbitLoader
Peak CPU Usage: 85%
RabbitLoader offers aggressive optimization techniques and built-in CDN integration. However, it pushes server resources to the limit. It’s fast—but could overwhelm lower-tier hosting environments.
WP Rocket
Peak CPU Usage: 29%
WP Rocket is a premium powerhouse—packed with features like lazy loading, preload, minification, and CDN integration. But all that muscle comes at the cost of CPU usage, which spiked higher than most in this test.
BerqWP
Peak CPU Usage: 24%
BerqWP is relatively new on the scene but promising. It provides good cache management and optimization tools but consumes a bit more CPU under pressure—especially during cache preloading.
LiteSpeed Cache
Peak CPU Usage: 17%
Highly optimized for LiteSpeed servers, this plugin leverages server-level caching and optimization. The CPU usage is higher compared to lighter tools, but its power is unlocked fully only when paired with a LiteSpeed-based stack.
RapidLoad AI
Peak CPU Usage: 16%
RapidLoad AI targets Core Web Vitals improvements. Its cache warmup is slightly more demanding than others but still well within a safe range for smaller hosting environments.
NitroPack
Peak CPU Usage: 12%
NitroPack bundles caching, CDN, and optimization in a single plugin. While it does a lot behind the scenes, it keeps CPU usage impressively low thanks to smart offloading and preloading techniques.
WP Super Cache
Peak CPU Usage: 9%
A no-frills caching plugin from Automattic (makers of WordPress itself), WP Super Cache has been around for years and still delivers. It’s simple, effective, and extremely light on resources.
FastPixel
Peak CPU Usage: 5%
FastPixel is designed from the ground up to minimize server load without sacrificing speed.
Its caching mechanisms are efficient, barely nudging CPU usage even when optimizing multiple pages. Ideal for shared hosting and anyone who wants a performance boost without system strain.
Key takeaways
- RabbitLoader: Most CPU-intensive in the test. While it delivers aggressive optimizations, it's not ideal for shared hosting or low-spec servers due to its high resource demands.
- WP Rocket: A powerful all-in-one caching plugin, but its feature-rich setup comes at the cost of CPU usage. Best suited for robust hosting environments.
- BerqWP: Offers decent performance but leans heavier on CPU during cache preloading. More suitable for experimental setups or mid-tier servers.
- LiteSpeed Cache: Delivers strong performance when paired with LiteSpeed infrastructure. Slightly heavier on CPU, but worth it if your host supports LiteSpeed.
- RapidLoad AI: Moderately light on CPU and focused on Core Web Vitals. A good choice for developers looking for balance between automation and fine-tuning.
- NitroPack: Smart optimization stack with solid CPU management. Set-it-and-forget-it style performance plugin for a broad range of sites.
- WP Super Cache: Lightweight and reliable. A great fit for minimal WordPress installs or legacy projects on tight hosting resources.
- FastPixel: The most CPU-efficient caching plugin in this test. Ideal for shared hosting, eco-conscious setups, and anyone who wants speed without sacrificing server health.
Top comments (0)