I think this is because reiserfs is better handling a lot of small files, while ext3 performes better with a few big files.
Is it possible that you are working with a fairly old linux distribution? Today's ext3 shouldn't have these issues any longer, otherwise Redhat wouldn't ship it as the only supported filesystem with its Enterprise distributions. A modern 2.6er ext3 has indexes and b-trees on top of the common ext3-layer, so even big directories shouldn't be a problem any more.
Regards Marten ---- Cyrus Home Page: http://asg.web.cmu.edu/cyrus Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html