Aleksey Korzun has posted some of the results from benchmarking he performed on various Memcached and Redis clients through PHP. His tests focused on multiple PHP client libraries, both user-land and extension based.
As some of you may know, I'm crazy about speed. So when I saw that people were happily using Predis as their choice of PHP client for Redis, I was a bit confused. Why use a client written in PHP for something that should be 'fast' like Redis? That kind of defeats the purpose - unless you don't really care about response times and scalability. [...] The performance difference piqued my interest. I wanted to find out just how much performance users are sacrificing by choosing one implementation over another.
He ran his tests on VirtualBox VM instances with the same specs and the same version of PHP installed. He tested various versions of the Memcached client, Redis client, Predis and the IgBinary extension. His results (Google spreadsheet) show the requests processed using each method based on this benchmarking script.You can visit the post to see the graphs of the results too.