Default Sort / IE7 Slowness

var oSettings = {'aoColumns'       : [{'bSortable':false},null,null,null,null],
                 'bPaginate'       : false,
                 'bProcessing'     : true,
                 'bSortClasses'    : false,
                 'sScrollY'        : '400px',
                 'bScrollCollapse' : true,
                 'bInfo'           : false
                };

$('#sometable').dataTable(oSettings);

Besides accepting the fact that IE7-JS is slow, I'm trying to see where the hang is. After profiling, I've noticed that it is spending a lot of time calling 'numeric-asc'. So why would this occur if there is no sorting going on?