jQuery.fn.append is unusually slow for large

jQuery.fn.append is unusually slow for large

This has come up while using the jquery.tmpl plugin.  With 1.4.2, Webkit has unusable times which can be reduced to the following simple cases.

In this case largeString is a joined array of <ul><li>brief text</li>(..3x li's)</ul> while $('#id') is an empty div.

Case: $('#id').append(largeString)

Safari/Chrome
Array length:1600
Render time:127949

FF3.5
Array length:1600
Render time:2524

Case: $('#id').html(largeString)

Safari/Chrome
Array length:1600
Render time:551

FF3.5
Array length:1600
Render time:1804

I'm having a hard time making sense of these results.  The webkit results show almost 3 magnitudes order difference. 

Thanks,
Thatcher