Changes in base-benchmark.html http://src.iws.cs.ovgu.de/source/rss/yui3/src/base/tests/benchmark/base-benchmark.html en Copyright 2005 Java Some perf improvements, based on mix usage. Y.Object would be faster still, but changes how Attribute addAttrs would need to work with configs (would need to remove hasOwnProperty check). Investigating/measuring that angle next. Fastest would be to cache the output of _initHierarchyData per class, but that's potentially unsafe. Investigating that also. See data in #2530356 /yui3/src/base/tests/benchmark/base-benchmark.html - 3fabb00ab96922fd2ed57b7d65f78351d8df5cde Satyen Desai <sdesai@yahoo-inc.com>