I saw in the Riptano "Tuning Cassandra" slide deck that the row cache can be detrimental if there are a lot of updates to the cached row. Is this because the cache is not write through, and every update necessitates creation of a new row? I see there is an open issue: https://issues.apache.org/jira/browse/CASSANDRA-860 for implementing write through in 0.8.
-JD