ReiserFS is a filesystem based on plug-in based object-oriented balanced tree algorithms developed mostly by Hans Reiser from Namesys. ReiserFS 4 is scheduled for a release this summer and Namesys have now unleashed a couple of benchmarks. Reiser4 was benchmarked against ext3 and ReiserFS 3. Reiser4 turns out to be way faster than V3, and for ext3, why don't you check out the results yourself? Hans Reiser states: "These benchmarks mean to me that our performance is now good enough to ship V4 to users", and he will be probably sending in a patch within the next couple of weeks to be included in the 2.6/2.5 kernel.