Shane Ducksbury has a showdown:
Caching is an important step in increasing the performance of many applications. It can be difficult to determine which caching solution is the best for your use case. Two likely contenders that will often make an appearance in your search for the answer are Redis vs Memcached.
In the green corner is Memcached (est. 2003), the classic, high performance caching solution. In the red corner is Redis, a slightly newer (est. 2009) but very mature and feature-rich caching in-memory database. Below, we’ll take a look at the differences between the two to help you make the decision which to choose.
I’ve personally had better experiences with Redis; my experience is that both work well from low to high load, and both have a tendency fall over at really high load.