Be careful to compare apples to apples. Sure, the memory-only crowd (e.g, redis) will post higher numbers, but Cassandra is the performance leader for scalable, larger-than-memory datasets. See http://www.cubrid.org/blog/dev-platform/nosql-benchmarking/ for example. (And this tests an old version of Cassandra; we did a lot of optimization on the read path for 1.0: http://www.datastax.com/dev/blog/whats-new-in-cassandra-1-0-...)