Memcached vs Redis: Choosing an Object Cache for WordPress

Memcached runs a multi-threaded architecture built around one job — storing and retrieving key-value pairs as quickly as possible, with minimal overhead per operation. That simplicity is a genuine strength: fewer moving parts means fewer places for something to go wrong, and its multi-threading scales cache throughput across CPU cores relatively cleanly as load increases.

Redis is largely single-threaded for its core command execution, which sounds like a step backward until you consider what that single thread is doing — supporting a much larger command set and richer data structures without needing to coordinate locking across multiple threads. In practice, Redis's single-threaded model rarely bottlenecks a typical WordPress or WooCommerce caching workload, since object cache operations are fast regardless.

Memcached stores a value against a key and that's essentially the whole interface — you can set it, get it, and delete it. For pure object caching, that's all you need, and the simplicity keeps overhead low.

Redis adds native support for lists, sets, sorted sets and hashes as first-class types, which opens up uses beyond object caching entirely — a sorted set makes a natural leaderboard or a time-ordered activity feed, a hash maps cleanly onto a product's attribute set, and a set handles deduplication tasks efficiently. For a WooCommerce store doing more than basic page caching — session handling, rate limiting on checkout attempts — those extra data structures are the practical reason to reach for Redis instead.