APCu vs Memcached: Which Cache is Best for WordPress?

When it comes to WordPress performance, caching plays a crucial role. Two popular caching solutions often discussed in the WordPress community are APCu (Alternative PHP Cache User) and Memcached.

What are the differences between APCu and Memcached, and which is the best for WordPress?

What is Caching and Why Does It Matter?

Before diving into the specifics of APCu and Memcached, it’s essential to understand what caching is and why it’s critical for WordPress performance.

Caching is the process of storing frequently accessed data in a temporary storage area (cache) to reduce the time it takes to retrieve this data. There are different levels of caching, including:

• Object Caching: Stores the results of database queries, API calls, and other time-consuming operations.
• Page Caching: Saves entire HTML pages and serves them directly to users, bypassing PHP and database queries.
• Opcode Caching: Stores compiled PHP code in memory to avoid the overhead of parsing and compiling code on every request.

APCu: What is it?

APCu is a user cache for PHP, designed to store PHP variables in shared memory for quicker access. It’s an extension of the older APC (Alternative PHP Cache) and focuses solely on user data caching, as the opcode caching functionality has been integrated into PHP’s core as OPcache.

Pros of APCu:

• Low Overhead: APCu is lightweight and adds minimal overhead to your server.
• Fast Data Retrieval: Since APCu stores data in the local memory of the server, it offers lightning-fast data retrieval times.
• Ease of Use: Setting up APCu is straightforward, making it accessible even for those with limited server administration experience.

Memcached: What is it?

Memcached is a distributed caching system that stores key-value pairs in memory to speed up database-driven websites like WordPress. Unlike APCu, Memcached can be used across multiple servers, making it a better option for more complex setups.

Pros of Memcached:

• Distributed Caching: Memcached can be deployed across multiple servers, allowing for scalable and distributed caching. This is particularly useful for large WordPress sites with high traffic or sites hosted on multiple servers.
• Versatile: Memcached isn’t limited to caching PHP variables; it can cache a wide range of data types and is supported by many applications beyond WordPress.
• High Performance: Memcached is highly efficient and can handle large amounts of data with low latency, making it an excellent choice for demanding environments.

APCu vs. Memcached: Which Should You Choose for WordPress?

Let’s compare them based on key factors that affect WordPress performance:

1. Single Server vs. Multi-Server Environments
   • APCu: Best suited for single-server environments where data is stored and retrieved from the same server.
   • Memcached: Ideal for multi-server environments or when scaling is a priority.
2. Ease of Use
   • APCu: Easier to install and configure, making it a good choice for beginners.
   • Memcached: Needs more advanced knowledge to set up, particularly in distributed environments, but greater flexibility.
3. Performance
   • APCu: Excellent performance for local caching, with minimal overhead.
   • Memcached: Provides high performance in distributed setups, but may introduce slight network latency in some cases.

Final Thoughts: What’s is Best Choice for WordPress?

For Smaller WordPress Sites APCu is often the better choice due to its simplicity, low overhead, and ease of setup. If you’re running a WordPress site on a single server and don’t expect to scale to multiple servers, APCu is likely all you need.

For Larger Multi-Server WordPress Sites Memcached is the better option. Its ability to distribute cache across multiple servers and handle large amounts of data efficiently makes it ideal for high-traffic sites and those hosted on more complex infrastructure.