"What's interesting to me is that it doesn't seem to be taking up time in defaultDisplay – which is our internal method for handling the first edge case you've described – but rather the native getPropertyValue called in curCSS to retrieve the current display value. However, that is even more disconcerting because removing defaultDisplay won't solve this issue. It seems that retrieving computed CSS for all of those elements is the bottleneck, which is very unfortunate because that isn't unique to .show()/.hide(). Maybe someone else could confirm what I'm seeing?"May not be .show() or .hide() that you should avoid, but instead a slow native call that the jQuery team might be able to point out to browser vendors... Or am I reading this incorrectly?