1) GUICtrlCreateListViewItem() - very quick 2) _GUICtrlListView_AddItem(ControlId) - MUCH slower 3) _GUICtrlListView_AddItem(ControlHwnd) - even MUCH more slower I think 1) and 2) should have similar time consume amount and not such big differences. I saw it's sources. Times in parenthesis are from another computer. All times are avg from several runs (all on 3.2.10 version) #include <GUIConstants.au3> #include <GUIListView.au3> $gui = GUICreate("listview it