APC vs. APCu Cache: Recommended For WordPress

If you’re looking to boost WordPress performance, caching is crucial. Among the many caching tools available, APC and APCu are two that often come up in discussions. But what’s the difference and which is better for WordPress?

What is APC (Alternative PHP Cache)?

APC, or Alternative PHP Cache, was one of the earliest caching solutions for PHP. It was designed to optimize PHP performance by caching the compiled bytecode of PHP scripts. By storing this bytecode in memory, APC reduces the need to recompile PHP scripts every time they are executed, resulting in faster execution and reduced server load.

Key Benefits of APC:

• Faster PHP Execution: Since the PHP code is already compiled and stored in memory, it doesn’t need to be recompiled for each request.
• Reduced Server Load: By minimizing repeated server requests, APC lowers the load on the server, especially on sites with high traffic.
• Memory Storage: APC stores the compiled bytecode in shared memory, allowing for quick access.

However, APC had some limitations. It wasn’t actively maintained after PHP 5.4, and as PHP continued to evolve, the need for a more modern and efficient caching solution became apparent.

Introducing APCu (APC User Cache)

APCu is essentially a stripped-down version of APC. While APC provides both opcode caching and user data caching, APCu focuses solely on user data caching. This was in response to the development of the built-in OPcache in PHP 5.5, which took over the role of opcode caching, leaving APCu to handle user data caching.

Key Benefits of APCu:

• User Data Caching: APCu is specifically designed to cache user data, such as variables and arrays, in memory for quick retrieval.
• Better Compatibility: APCu is fully compatible with modern PHP versions and works seamlessly alongside OPcache, which handles opcode caching.
• Simplicity and Efficiency: With a more focused role, APCu is simpler and more efficient in handling user data caching without the overhead of opcode caching.

APC vs. APCu: Which is Better for WordPress?

For modern WordPress sites, APCu is the recommended choice over APC. Here’s why:

1. PHP Compatibility: APCu is compatible with the latest PHP versions, whereas APC is outdated and not supported beyond PHP 5.4.
2. OPcache Integration: Since PHP 5.5, OPcache has been the go-to solution for opcode caching, making APC redundant for this purpose. APCu complements OPcache by handling user data caching.
3. Performance Gains: With APCu, you can cache frequently accessed data in memory, reducing the need for repeated database queries. This leads to faster load times and an improved user experience.

How to Implement APCu on WordPress

Implementing APCu on a WordPress site is straightforward:

1. Ensure Compatibility: First, make sure your server environment supports APCu and that you’re running a compatible version of PHP (typically PHP 7.0 and above).
2. Configure WordPress: After installing APCu, you may need to adjust your WordPress configuration to leverage APCu for object caching. Plugins like W3 Total Cach can be configured to use APCu.

Conclusion: The Modern Choice is APCu

APCu is the clear winner over APC. With its focus on user data caching and compatibility with modern PHP versions. Pair it with OPcache for opcode caching, and your WordPress site will be primed for speed and efficiency.