What is the best for a simple k/v cache in terms of read performance and memory usage?

In our web app, we need a simple k/v cache, the read performance is most important, followed by memory usage, memcache or redis, which is better for that?

I googled a little bit, seems redis is better than memcache in general, and redis has more functionalities.

But in my case, I don't need those advanced features.